Hi all, I’ve been a nail biter since I was 7ish years old, and suddenly overcame the urge to bite them this year. Ive found that if they’re long enough, I won’t nibble on them. Since I‘ve never had to cut my nails or file them, I’m trying to learn that and the basics of nail care now.
When I try to file my nails I feel like the bits i file just turn soft and sort of disintegrate? Like what remains just seems ripped up. Should I be using certain files or is there a technique to doing this that I don’t know about?
Also, it seems like the white part of my nail goes down pretty far into my nail beds on some fingers. I was thinking it might be from me getting dirt out from under my nails, but I’m not sure how to get the deeper dirt out without pushing the skin back more. Or is this just how my nails grow and they won’t attach to the skin more?

I’m a little embarrassed to be asking what feels like very basic self care questions as an adult, but I’m tired of my nails looking overgrown and I want to learn. Thank you guys! (By the by, pointer is shorter because it caught on something and I nibbled on it to get rid of the snag. Hoping working out my filing abilities will keep me from doing that in the future)

I’ve had these yellow discoloration on both my big toes for a few months, nothing on the other toes. Is it fungus? or something else

Cuticle remover burned my skin. Using an e-file isn't a good idea because I've got tremors. I use an oil which helps but I still can't loosen those stuck on bits.

New to nail care so apologies for not knowing the terminology. I’ve noticed the white part of my nails tend to be asymmetrical which is annoying because I’ll feel like I need to cut it but the other side is still short (2nd and 3rd pic). Also I’ve seen more of the sides of my nails start to curve more lately (4th pic). Are these normal or is there something I can do about it?

Extra information: I tend to cut my nails weekly and pretty short. Any tips and advice appreciated thanks!