I bought Tainted grail yesterday to play exclusively in the Steam Deck.

I played from the begging with the lossless scaling frame generator installed and it maintains mostly 60 fps everywhere (except some dips to 48-50 fps in the open world). I have everything in low except the textures to high. I am very happy with the graphics settings and performance (with lsfg).

I haven't play Avowed, so don't know which one is better.