Main character volume (whether that's Eivor or Layla) is much louder than the characters that they're speaking to. What's odd is that this only appears to exist when playing with a Mouse & Keyboard. If I so much as wiggle the joystick on a connected controller to switch the control scheme to a controller during a scene where Eivor is talking, I can immediately hear his volume lower. This is a duplicate bug to multiple other threads, but since the most recent mentions I can find are from ~2 years ago, I thought I would try again in the hopes that the developers might be able to fix it now, especially since it seems simple enough to fix: if(controlScheme == keyboard){eivor.volume = eivor.volume * 0.8;} (obviously not THAT easy, but still, it's pretty clear that lots of people are still experiencing this, so maybe revisit it? Links to a few of the other threads below.
https://discussions.ubisoft.com/topic/97713/resolved-eivor-s-voice-is-much-louder-than-those-of-npcs-post-here?lang=en-US
https://discussions.ubisoft.com/topic/79681/problem-with-sound-main-character-is-much-louder-then-others-npc/6?lang=en-US
I also haven't seen this bug listed in any of the known issues threads or support megathreads.