First, Make sure your MacOS is up to date in [System Pref -> Software Update].
Try disabling the auto brightness in [System Pref -> Display] (automatically adjust brightness); and [System Pref -> Keyboard] (adjust keyboard in low light).
If you have a custom color profile, switch to the default "color LCD" one in [System Pref -> Display -> Color]. https://www.youtube.com/watch?v=MsK5zmRpg5k
Resetting PRAM might also help: Reboot, hold CMD + Opt + P + R until the apple logo shows, then let go. https://support.apple.com/en-us/HT204063
Create a guest account or new user in [System Pref -> Users & Groups] use the + icon to create one. Press the Apple logo at the top left to [log out] and test using the new account.
You can also try running the Apple Diagnostics test to see if there's a hardware problem by restarting and holding "D" until it boots up.
For hardware-related repairs: If you have AppleCare+, it wouldn't hurt to get a price quote, because 2016+ MacBooks have a T2 chip that rejects non-Apple certified hardware repairs and parts. If looks like the minimum cost for a repair for the screen could be $99-$300. https://support.apple.com/mac/repair/service
This site says to expect around $455+ for an out of warranty screen repair.
Hope this helps! Best of luck! 😊