This HU isn't very fast so can't really run a bunch of latest apps without frustrating pauses. Following are some ways to make it go faster. The basic solution is to run simpler apps.
Avoid running high performance app (such as nav) continuously. Here is a simple solution ( #4382 )
A fan surprising made quite a bit of improvement. Post #4436
Do these steps before risking firmware updates. Above 2 may have much bigger performance improvement and much lower bricking risk.
When HU wakes from sleep, xyauto launcher is very quick. This is because it didn't exit during sleep. Aftermarket launchers can also have this behavior
https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-89849612
Customized nova launcher seems to wake very quick even if exit during sleep
Best option is probaby just use the phone (CarPlay or Android Auto) to run navigation which is much faster than the HU. I set mine as follows
Use the 6pin USB port USB3 (default is set to USB2 so need to change it in System Settings)
App auto starts when plugged in. Starts up faster, runs faster
Charges the phone (USB need to be set to host rather than device mode)
No wireless pairing confusion with multiple paired phones in the car.
LTE connected
HU SIM has limited LTE bands for US market but some users reports working. For rest of the world, LTE band matches China (HU has Chinese company made cellular radio) and should work well.
Offline
Google maps can work offline using downloaded offline maps. Searching without internet connect will be compromised.
Versions and UI
Google Maps app version can be updated to the latest via Google Play Store (requires sign-in). However, a couple of UIs seems different than latest versions on devices with latest OS. For example, my iPhone Google Maps seems to have proper light/dark theme displays even when not navigating.
I read older Google Maps version running on older Android version doesn't switch to darker night time theme unless it is in navigation mode (destination chosen and routing navigation). This can be very bright when driving at night and not using navigation (can be improved by setting HU night mode brightness to lowest and turn on eye protection which reduces blue light) If not using navigation mode, the map is always pointing north rather than driving direction.
iGO Navigation is a very light weight app. It is fast, automatically animate map with your location when start driving and auto switch to darker color theme at night. Downside is destination search is quite old style (enter city, street name, number, etc. in sequence of boxes rather than google's nice and quick search capability).
See also here:
https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-88494035
https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-88930915
Tried many other and most aren't very good. Sygic is good but free version does have ads that triggers online connection requirements. Defeats the offline app.
Organic Maps can be used completely offline without disadvantages and doesn't collect your personal data. It's available at Google Play Store and F-Droid.
Magic Earth and Mapfactor Navigator can be also used offline.
Here is a small review for HUs for the AC8257 and AC8259 processors:
https://android-headunits.com/the-ac8257-processor/
https://android-headunits.com/the-ac8259-processor/
For comparison a small review of ultra low end 8227L processor:
https://android-headunits.com/8227l-processor/
https://android-headunits.com/be-wary-of-faked-android-headunits/
These HUs are not that fast. Here are 2 posts along with Geekbench score:
https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-84414443
https://xdaforums.com/t/ac8259-cpu-based-hu-problems-questions-mainly-yt5760.4171219/post-89704600