Why is my iMac screen dim and/or stage lighting?

Hi everyone!

So, I’ve been plagued by a dim screen/stage lighting issue with my 2017 27” iMac. I first noticed how dim my screen was a couple of months ago. The brightness adjuster wouldn’t start affecting anything until it was below 50% of the adjustment bar. So, my iMac was essentially just running at half-brightness. I noticed in some darker UI programs, that there was some severe stage lighting going on. I was to the point where I was about to order a new LED logic board (well, maybe not order bc I couldn’t find ANY in-stock)… However, I found that resetting my NVRAM would buy me a few days of blissful, easy to work with, full screen brightness. This leads me to believe that it’s some sort of software issue. At one point, this reset worked for works. Now, I have to do it every three or four days.

There’s SO much info on stage lighting for MBPs, but barely anything for iMacs. Even less for NVRAM seeming to temporarily fix the problem. Any insight into this would be monumentally appreciated as this is my main machine and I’d love to have it performing as it should be. Thanks!

PS: Not sure if this helps or not, but I can’t help but pin the correlation that this started happening right around the same time that I started using Adobe AfterEffects. I’ve since ceased using it on my iMac. I’m running macOS Catalina v.10.15.7 too.