@durp @Flappie
I think I've found the problem.
Sometime ago, I adjusted my MFD screens' brightness through the Adrenalin control panel's "custom color" settings for each display, since the Hornet's MFD export was too dim.
That was the culprit. I disabled custom color and everything is back to normal. That was the last thing I suspected since I seriously thought the problem was one of the numerous updates that happened all at once.
I am being cautious though since every time I thought I'd figured it out, I was proven wrong a couple of days later. Keeping my fingers crossed.
m005106's post in Massive stuttering(can only be resolved temporarily after flushing fxo and metashader folders) was marked as the answer