Play as the bad guys in a single dungeon room - Roguelike survival against adventurers

I'm working on a concept, and wanted to hear if anyone knew of anything very similar. I'd also love to hear critiques of the ideas if any.

- Fully cooperative, hex-based combat game
- Each player selects one "big bad boss" character to control (e.g. Lich, Dread Knight, Wraith King, Orc Warlord, etc.)
- Players will have a few unique traits, but the uniqueness will primarily be derived from a small starting deck of approximately 12 cards representing character powers. Players will begin each round with 5 cards, and will Move + choose 2-3 card actions per round. They will discard any unused cards and draw up to 5 at the end of a round.
- The game board will be relatively small, approximately 10 x 10, but can be populated with enough walls, hazards, traps, treasures, imprisoned standees, and other objectives that the it will feel meaningfully different each scenario.
- The object of the game will be to defend against the nuisance of invading adventurers. These enemies will come in many varieties (knights, mages, bards, any number of "good guy" tropes). The board will start with just a few enemies, but 1-3 more will be introduced each combat round. There may be an invader deck that is drawn from each round, stating something like "1 Normal Cleric, 1 Elite Paladin" and where to place those new arrivals.
- The AI controlling the enemies will rely on a small action deck, in the vein of Gloomhaven.
- I want there to be a great amount of transparency in the enemies' upcoming actions so the players can choose their actions with full knowledge. The approximate order of combat is: 1. Enemies announce Move & Action. 2. Enemies Move and may engage a player in melee combat. That player cannot move without killing the enemy or causing some other disrupting status effect. 3. Players choose Move & Action. 4. Player fast Actions 5. Enemy Actions. 6. Player slow Actions.
- The "primary" objective of each scenario is to protect spaces on the map. I was thinking something like "phylactery pieces", where once the enemies destroy 5 of them, you lose.
- A scenario will end after approximately 6-7 rounds after completing side objectives such as "eliminate 3 elite enemies" or "eliminate the dwarven king". Players will be rewarded with treasures (simple additional abilities, such as +1 move) and additional cards to improve their decks, depending on how well the side objectives were completed. Failed protection of the primary objective elements (phylactery shards) will carry over to the next scenario played. E.g. if 2 shards were destroyed, only 3 shards will carry over into the next scenario.
- I envision it as a "roguelike" game, in that the team of players will continue through increasingly difficult scenarios, accumulating better cards and better treasures.

Thanks for your input!