I've hit lag quite a few times with Hogwart's Legacy. Dropping the graphics quality down helps but even at the point it looks like shit it often still stutters, especially during complex combat situations (the point at which stuttering is least tolerable).

I love the Steam Deck and they do a really, truly great job at tuning profiles of most games to run well, but the most demanding AAA games do sometimes hit a perf ceiling.

If you're curious about the details and you haven't seen it before, you can enable metrics/stats in settins and see a screen overlay of your performance. As someone who frequently keeps htop open on my laptop while working, I appreciate this feature :-)