It's probably a combination of human nature (you remember the bad more than the normal) and mechanics.
How familiar are you with 5E D&D?
Whether you are or aren't, BG3 has it's own customization layer on top of that that you have to learn.
If you know how things work it's not hard to hit things.
If you need more specific help, post some more specific info about who is missing, what weapon/spell are they using, what are their stats, etc.
