definitely having the same kind of issue. playing in borderless windowed here, but does it with the other two options as well from what i can gather.

for me, everything like bgm and ui sounds are perfectly loud and clear, but any sound coming from characters (skills, footsteps, emotes, etc.) very 'far away' and muffled sounding, but not as though the 'distance from character' sound settings have been tinkered with. it's usually fine when i log in, but then it eventually does this when i enter a duty or do anything. not a huge thing that will impact my gameplay, but definitely a bit of an annoyance since i'm a very sound-oriented player.