Same issue. I think it has something to do with the recent update enabling GPU acceleration. I'm using KDE with 225% scaling, but Steam doesn't respect it as of now.

Another day, another Fortigate CVE 😬

Specialisation is key, especially at the start. Focus on your main skill (eg Fighting+weapon of choice, or Spellcasting+Fire Magic, …). You can probably skip levelling Dodging/Armourer for until you are more comfortable with progressing. I usually turn Dodging or Armourer at earliest in the Lair, but it depends a lot.