It is often said that the photographer makes the picture, not the camera. Nevertheless, landscape photography was built on a tradition of stunning imagery achieved with large and medium format cameras. In keeping with that tradition, my advice is to stretch your budget to purchase a camera (and lenses) that produces the best image quality possible. Some key considerations are low noise, good dynamic range, and accurate color. I further recommend, in keeping to that goal, to buy only a full-frame camera. There are of course legitimate reasons for buying smaller APS-C cameras (cost for one) and they are still capable of producing images that will not disappoint. But in my opinion, full-frame cameras are the definite sweet spot between cost and high image quality.
To help with your search, there are many resources available that review most brands. Below, I’ve listed the websites I often consult.
Digital Photography Review
DxO Mark
Photozone
Imaging Resource
How Many Pixels?
You needn’t equate high image quality necessarily with pixel count. Some high-end full-frame cameras now rival medium-format cameras in resolution. But are all those pixels necessary to produce a gallery-quality print? Many feel that high-megapixel cameras are just the ticket for landscape photographers who want to produce “large prints." It was never clear to me just how large “large” is, but regardless, there is one fundamental fact that may make it a moot point. That is that the human eyesight has finite resolving power at any given distance and, beyond that, more resolution simply isn’t perceived.
Convention is when you view any print, from a 5x7 inches to a billboard, the appropriate viewing distance is no closer than the diagonal length of the print. You can demonstrate to yourself that in practice, a natural viewing distance is even a little further away. Given that premise, then you’re not likely to see much, if any, improvement in resolution beyond a very-good 12-megapixel camera (or there about) no matter how large the print is.
Unfortunately, many of us love to scrutinize up close at the fine details of a print, even if it is contrary to its proper presentation. Then there are photographers (myself included) that find security in all that extra detail. Maybe someday you’ll make a wall mural or you need extra cropping room.
So, if your “big print” is 16x24 inches and instead of viewing it at 29-inches you view it closer than 12-inches (and you have excellent eyesight), you'll need a high-megapixel camera along with good optics. But that’s if you want the confidence your prints can withstand scrutiny at any distance. Otherwise, if you display your work in a more practical gallery-like setting, then a camera in the over-twenty megapixel range will be adequate most times and still provide sufficient cropping margin. The main point is that while it’s fine to be tempted by the new ultra-high pixel cameras, just remember that dynamic range and noise (two key image-quality criteria) may suffer as a result.
The DSLR is available in two different sensor sizes, full-frame and the smaller APS-C. The configuration uses a mirror to support an optical viewfinder as opposed to an electronic viewfinder used in mirrorless cameras. While this made the DSLR the preferred optical viewing and focusing system (especially for action photography), the current generation of electronic viewfinder systems have mostly closed the gap.

Nikon D850: This popular 45.7 megapixel full-frame camera supports WiFi, 4K video, tilting touch-sensitive LCD, GPS, and Bluetooth. Though likely to be discontinued, recent deep discounts make this an attractive option to those who want high-end quality at a budget price.
Full-Frame Sensors and APS-C
The full-frame sensor is equivalent in size to a 35mm film image. The smaller APS-C is derived from the Advance Photo System film standard introduced in 1996. Full-frame sensor cameras are usually associated with better dynamic range, lower noise, and finer image detail. They also accommodate legacy 35mm lenses without suffering the effective focal-length increase of a smaller sensor (aka “crop factor”).
On the other hand, APS-C cameras have their own unique advantages. They are less expensive, smaller, and lighter than full-frame cameras. Additionally, the APS-C crop factor — though it reduces wide-angle coverage — increases the effective focal length of a telephoto lens by over 50%, which is an advantage in wildlife photography. Nevertheless, unless there is a very specific reason to choose an APS-C camera, I strongly recommend you go with a full-frame format.
RIP DSLRs?
It shouldn’t be surprising that all the latest cameras from the major manufacturers are all mirrorless. I think it’s fairly clear that mirrorless cameras are no longer just an optional choice to DSLRs, but soon to be the only choice. One example is the numerous Canon EF lenses (their DSLR mount) that are being discontinued while all their new lenses are for their mirrorless cameras. Simply put, the handwriting is on the wall. If you’re in the market for a new camera, you best future-proof your purchase by considering only mirrorless cameras.
Micro Four-Thirds (4:3) System
Olympus and Panasonic market mirrorless cameras that have all the appearances of a DSLR, but use a smaller sensor than APS-C cameras. The Micro Four-Thirds is a standard developed by Olympus and Panasonic that departs from the 3:2 aspect ratio of full-frame and APS-C sensors. The 4:3 aspect ratio is more efficient at placing all the pixels where they’re needed most because it better matches standard print sizes such as 8x10 or 11x14 inches. When you crop a 3:2 format to a standard print size, you sacrifice a portion of your sensor’s pixels. Also, the 4:3 ratio has a shorter diagonal relative to a 3:2 ratio and that allows the optics to be sized more efficiently. The downside is the four-thirds sensor is approximately 30% smaller than an APS-C sensor and, despite the more efficient 4:3 ratio, image quality and low-light performance take a commensurate hit.
Full-Frame Mirrorless
Sony was first to kick off the full-frame mirrorless camera revolution. The other manufacturers eventually caught up and now there is a wide selection to choose from. Most of the past issues with mirrorless cameras have been resolved, clearing the way for mirrorless cameras to supersede full-frame DSLRs. A few nagging issues persist, one being a shorter battery life. Another is dust exposure during lens changing, unless there’s a shutter closure option.
Riding the wave with the mirrorless revolution are the advances in full-frame sensor technology. Sony in particular was first to promote the BSI (Back-Sided Illuminated) sensor that allowed for higher megapixels while minimizing noise and extending dynamic range. Then they doubled-down with the “stacked” BSI sensor that further enhanced image quality while greatly accelerating readout times (good news for video capture and electronic shutter usage).

Sony Alpha 7R IV: 60.2 megapixel resolution with upgraded OLED, weather proofing, and AF tracking.
Canon, who always went their own way with sensor development, introduced their first stacked BSI camera, the R3. This camera is positioned between the R5 and their pro EOS-1D X Mk III.
I recently upgraded from my old DSLR Canon 5Ds to the mirrorless Canon R5. My major motivation was the superior noise performance over the 5Ds. Though not a BSI sensor, the improved noise performance is due in part to moving the backend signal processing to the sensor chip. In addition, I’m enjoying many of the latest features that the 5Ds lacked, but a few are more annoying than helpful. For example, I had to disable the touchscreen so I didn’t inadvertently reposition the focus point (you can’t independently disable that feature). Another is the short LCD preview time when in the power-saving mode.

Canon R5: My latest acquisition, a 45 megapixel high-performance camera that includes all the latest features. It’s totally compatible with my legacy EF lenses when using Canon’s mount adapter.
If you have the means to part with some serious cash, a medium format body with a digital back from Hasselblad or Phase One is the choice for ultimate image quality. Except, when you weigh the substantial cost increase to what practical improvement you get in image quality, it’s difficult to justify it over a high-end DSLR or mirrorless camera. You also have to factor in the increased weight and size when trekking out in the field. Also, medium format lenses are, on average, significantly more expensive with less variety.
Mirrorless to the Rescue
There is now a new generation of medium format mirrorless cameras that are smaller, lighter in weight, and substantially lower in cost. Examples are Hasselblad’s X1D II 50c and the Fujifilm’s GFX 100S. They are priced competitively against high-end pro-DSLR cameras and are similar in size and weight. Where they fall behind are in frame rates and focusing capability, all a possible deal-killer for sports and wildlife photographers.

Fujifilm GFX100S: A whopping 102 megapixel medium format camera that costs less than many pro DSLR cameras.