Could you post your audiogram, as even if you up to 90bB in just the higher frequencies, I’d think UP would be ok, but power receiver could be suitable as well, really need to see the complete audiogram.
Yep could be, MPO or just the settings for loud sounds need to be adjusted, post a screenshot so we can see what’s going on.
Why? Linear is very analogue sounding, maybe you should be using non linear.
Yes absolutely, set your level correctly on this, if you choose first time user it’s gonna be way under what an experienced user would want.