Posture corrector that works?

Hello everyone,

I wanted to ask if any of you know of a good posture corrector to, well, correct my posture lol I've been stuck on a computer for about 15 years, but last year I noticed I was starting to get a little lump on the back of my neck and I realized I didn't want to look like Quasimodo, so I've been trying my best to correct my posture with exercises and mostly strength workouts, and while the lump is now gone (maybe it was fat? who knows), I still have a horrible posture while walking, while sitting, while standing... I really try to fix my posture as soon as I notice I'm slouching but like 3 seconds later I'm slouching again.

I tried to use a posture corrector, but since it's only for the upper back, my lower back still wouldn't stay in the correct position, and I would eventually find a way to slouch. My belly is not totally free of fat, but it looks much worse than it is since I'm slouching all the time.

Anyway, just throwing the question out there in case someone has a solution, and thank you! :)