28th at World Championships, Senior Division
14th at Philippines Premier Ball League
14th at Malaysia Premier Ball League
Ceruledge ex is a very straightforward deck to play. Your goal in every game, in every matchup, is to get Ceruledge ex out, get Energy into the discard pile to pump its attack, and hope that that carries you to a victory. While it doesn't have many tricks to alter its Prize map beyond Briar and the standard 2 Boss's Orders, it has good answers to low Ionos (Revavroom will draw you out of it as long as you hit a single Energy or Night Stretcher) and retreat locks (4 Jet Energy).
Ceruledge ex has the dubious distinction of having a losing matchup against Gholdengo ex (based on Limitless stats), despite being a Fire-type deck. This would be reversed after Mega Evolution gifted the deck the Lunatone + Solrock engine.
Get Charcadet and Varoom down and evolve them as soon as possible. Revavroom will sit on the Bench providing draw support, while Ceruledge ex stays in the Active attacking. Use your Supporters, Items, and Rumbling Engine to find Energy to attach to Ceruledge ex or Munkidori, or to toss into the discard pile to increase Ceruledge ex's damage output.
This deck virtually has only one attacker, Ceruledge ex. No need to worry about choosing the right attacker for the situation (the answer is pretty much always Ceruledge ex), just get fast at multiplying by 20 and adding 30. As a baseline, 9 Energy in the discard pile hits 210 damage, enough for a KO on ex Bench-sitters. The deck plays a relatively high Energy count to accommodate Ceruledge ex's attack.
A consequence of attacking exclusively with Ceruledge ex is that you lose really hard to walls. The Crustle matchup is virtually unwinnable, since a single Energy attachment into Ascension means you cannot touch them for the rest of the game, and they can Superb Scissors you at their leisure. Milotic ex is also unbeatable, though less common, and its pre-evolution doesn't have Ascension. Neutralization Zone blocks all damage, and you only have 1 counter Stadium. (FYI, the decks that play it are Mill, Roaring Moon/Dudunsparce, and Froslass/Munkidori without Marnie's Grimmsnarl ex.)
Ceruledge ex has a second attack, but the deck doesn't bother playing Psychic/Metal Energy to power it up (though some people try!). It ends up hurting you against Mew ex and Team Rocket's Mimikyu, as they can copy it for a 1HKO.
In a pinch, Munkidori can attack with Luminous + Fire Energy. This makes it a bit easier for Ceruledge ex to finish them off, risks their attack on a coin flip if they decide to stay in, and disrupts their Prize map by leaving a 1-Prizer in the Active Spot.
This deck wants to go first, as it's a Carmine deck AND it wants to attack with an Evolved Pokémon (Ceruledge ex) as soon as possible. Going first also lets you get "under" the opponent's Evolutions when you don't have that many Energy in your discard pile to score KOs on ex's yet.
Brilliant Blender. It serves several purposes: milling Energy to pump Abyssal Flames, milling Pokémon so you can Night Stretcher them back to your hand, or thinning your deck so you have better odds of drawing into Boss/Briar for game.
Hawlucha: Small damage mod.
Cornerstone Mask Ogerpon ex + Fighting Energy: A wall to improve the Gholdengo ex, Charizard ex, and N's Zoroark ex matchups.
Professor Turo's Scenario: Removes 2-Prize liabilities from the Bench, provides an additional answer to retreat lock, and denies 2HKOs on Ceruledge ex (while also getting the attached Energy into the discard pile).
Academy at Night: Lets you stash a card that you don't want to discard before playing Carmine or Professor's Research, or want to keep safe from an opposing Iono. Also draws you more with Revavroom, though you must combo it with a shuffle effect or you'll just draw into the same card that you put on top.
Medical Energy: Alternative to Munkidori.
Like with Mew ex in other decks, Ultra Ball is your best "combo piece" for reducing your hand size so Revavroom's Ability draws you more cards. Earthen Vessel is another discard outlet that doesn't discard as many cards, but can find Energy for the Ability.
If you have both Rumbling Engine and Carmine/Professor's Research available for the turn, which one to use first usually comes down to whether you have Ultra Ball and enough fodder for it in hand. If you already have the Ultra Ball (or if your hand is low to begin with), use it and draw back up with Rumbling Engine, then continue playing out your hand and refresh it again with Carmine/Research. If not, use Carmine/Research first and hope that they draw you into an Ultra Ball for Rumbling Engine.
If you have an Energy and Carmine/Research in hand, your instinct might be to attach the Energy before you play the Supporter, because you might draw into a hand with no Energy and miss the attachment for the turn. This line of thinking may be right in other decks, but not this one! The biggest reason for not attaching the Energy first is that it will pump Ceruledge ex's damage if you let it get discarded. As for missing attachments, just count the number of outs you have: 15 Fire/Luminous Energy (more than any other deck in the format), 2 Earthen Vessel, 3 Night Stretcher... you're actually VERY likely to draw into another Energy off the Supporter, so go ahead and discard with confidence.
You can spend Energy on retreats in order to get them into your discard pile. If you have two Ceruledge ex's with Fire Energy, one Active, one Benched, you can attach an Energy to the Active one, retreat it for the Benched one, and attack for 40 more damage. You can also attach Jet Energy to any 1-Retreat Pokémon on your Bench and immediately retreat to your attacking Ceruledge ex (this line is also effective at clearing Special Conditions).
Your typical targets for Brilliant Blender depend on the stage of the game when you play it. If it's early-game where you're still setting up AND you also have Night Stretcher in hand, you can discard a Basic Pokémon like Squawkabilly ex and retrieve it immediately with said Stretcher. If you don't have Night Stretcher in hand, you'll want to discard Ceruledge ex and/or Revavroom so that a later topdecked Night Stretcher can turn into either of those Pokémon. Either way, the remaining Brilliant Blender discards should be Energy.
If it's mid-game and you already have Ceruledge ex and Revavroom on the board, usually you'll just discard 5 Energy to get Abyssal Flames' damage up. If you still have Earthen Vessel in your deck, try to keep a Basic Energy in it so you'll have a target if you draw into Earthen Vessel. Also, try not to discard Jet Energy, as you might need it if they Boss Revavroom up.
If it's late-game where you either don't have or can't afford to discard any more Energy, you'll just use Brilliant Blender to discard dead cards from your deck; things like Buddy-Buddy Poffins or evolving Basics. If it's a do-or-die situation where you need to draw into and play Boss's Orders or Briar next turn to win, all other Supporters become Blender fodder.
In the late game, there are two ways you can inadvertently screw yourself out of a win. The first is drawing too aggressively and decking out. Count the number of cards in your deck and plan to have more cards left in there than attacks you're going to need to win, and hold off on the draw Supporters and Rumbling Engines if necessary. The second is running out of Energy and getting a non-attacker stuck in the Active Spot. Before you get to a low number of cards in deck, use a search Item to check how many copies of Jet Energy you have left in the deck. You can also try to preemptively attach an Energy to Revavroom so you can retreat it with another non-Jet attachment if they Boss it up.
For in-person play, you are allowed to rearrange your discard pile (but not split it into two piles) to count Energy more easily. (If you are playing on PTCGL, the game keeps track of how many cards of each type you have in your discard pile automatically, and also calculates the amount of damage Abyssal Flames would do when you view it.)