WIthout the kernel it just isnt really working as intended. I do however understand that you're scared of unlocking bootloader which is fine.
The issue happens at random instances. If, however, I'm able to capture it, I'll share the images here
@Danishblunt Thank you so much for the fix! Just tried it out last night and black crush is gone in low brightness. Even the grainy screen is reduced too (especially on Discord app).
No problem! You simply got rewareded for finding it 😊