Hey!
I just bought Avadon 3 on Steam, and I think I have the same issue. I get the same symptom/error at least.
I'm on a 14-inch, 2021 MacBook pro.
I did a quick test and I don't have the issue with Queen's Wish 1-2, Avadon 2, Avernum 1-3 (the remakes), only Avadon 3 (of course, the one I wanted to play 😅).