Question Secondary monitor glitching and flashing horizontal lines ?

[pigeonsandrats]

Hi y'all! My second monitor is refurbished and purchased in 2016 so this could be a coincidental end of life glitch but I've been experiencing these flashing horizontal line glitches. This spontaneously started happening when I downloaded Treesize Free to scan my files since I was trying to free up some space. I never actually deleted any files through this software, just scanned to see where the bulk of my storage was. From what I've looked up, problematic apps could potentially be the cause of this but I've since deleted it and restarted my PC a few times and no solution. I've tried messing with the hertz settings, updating graphics drivers, and testing out cables and connections. Even when disconnected from my PC, it glitches on a black screen so it seems isolated to just the display.

I think potentially, it could just be the monitor giving up but I wanted to see if any smarter people had any suggestions before I ditch and suffer with one display haha. I'll provide a photo below, thanks in advance to any wisdom!

https://imgur.com/a/v0JeDGE