Need a new first-person dungeon-crawling RPG? Perhaps it's time to check out Monomyth. The devs just updated it with better Steam Deck and gamepad support.
The games features a vast, interconnected game environment. Wander from the highest towers to the lowest caverns, find secret chambers, uncover hidden passageways and explore a multitude of differently themed areas. This is backed up by a highly interactive environment filled with items, puzzles, monsters and various peaceful inhabitants. An interesting dialogue feature too that has a keyword-based system.

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With the latest update "EA2.0.1a" the developer mentioned it has lots of improvements for Steam Deck compatibility, including "significant enhancements to gamepad controls". Changes:
* Fixed unresponsive/unfocused buttons in menu navigation via gamepad
* Added three minor sub-area soundtracks
* Adjusted the gamepad layout preset (Steam Deck)
* Adjusted the main menu for 16:10 screens
* Fixed a bug in gamepad controls that would re-open containers after taking all items from them
* Added gamepad controls overview
* Added gamepad/keyboard glyphs to tutorial texts
* Right-clicking textboxes will no longer open a context menu
* Fixed gamepad freeze on exit prompt
* Fixed item dropping bug on looting container
* Added tooltips
The game should be fully playable with a gamepad/Steam Deck now. The only missing features are an automatic virtual keyboard for textboxes (you can open one manually through the Steam button on your Steam Deck) and a few special grips for things like opening the journal.