Avowed sort-of works on the Steam Deck, though shaky performance means it's not the ideal way to play Obsidian's RPG.

In addition to crashing on startup on the ASUS ROG Ally in hardware writer Nick Evanson's Avowed performance analysis, I've found that the game runs booboo at best on the more ubiquitous Steam Deck. Avowed remains tagged with an "unknown" Steam Deck compatibility rating on its store page,

If you’re a Steam Deck owner hoping to explore the Living Lands of Avowed on your favorite handheld, I have (mostly) good news.

Avowed runs pretty well on ROG Ally as long as you're playing at the right settings. But you won't want to play on Steam Deck.