Been having trouble with my GPU for months now

Computer Type: Desktop

GPU: Radeon RX580 2048SP

CPU: Unsure

Motherboard: Unsure

BIOS Version: Unsure

RAM: 16GB

PSU: Unsure

Case: Unsure

Operating System & Version: WINDOWS 11

GPU Drivers: Latest AMD drivers

Chipset Drivers: Unsure

Background Applications: DISCORD

Description of Original Problem: Has a bunch of pixels everywhere when booting up. And has two long lines across the screen

Troubleshooting: I've tried taking the gpu out and putting it back in. I’ve used a ddu to uninstall and reinstall the drivers. I’ve tried different outlets and extension cords. All of them have only temporarily fixed the issue. I tried borrowing another monitor but that didn’t work at all. I took it to a repair store but it worked fine there.

Ive never been very well versed in computers, so I don’t know what a lot of stuff means or where to find it.

edit: I’m sorry for the unsure‘s with the specs, I’m not too versed in knowing what means what. I tried taking a pic of my specs in case that helps.