The worst black belt is still a black belt.
If you’re an insecure brown belt, you don’t become a secure black belt when you get promoted. At least that’s what I hear from the black belts I talk to. I have a brown belt now and will write an update when I eventually level up, but suspect a black belt won’t affect me much. Going to purple and brown did little for me. Only mat time had an effect.
If you’re a white belt, you’re probably not that good. But you’re better than someone. You’re better than yourself from six months ago.
I know a runner. She runs all the time, and sometimes races. Some days are slower or faster than another. She still runs.
It’s the same with golf. It’s that way with video games. It’s the way with anything. You don’t need to prove your rank every day. You just need to keep going.