Have you encountered a display issue that some screens are horizontal blue lines in browser?
This seems like an Graphics issue with newer Mac (I’m on MacBook Pro 2019 16") on Apple’s end.
I haven’t experienced this problem on Safari.
Disable Hardware Accelerations. ⌘ + , to open Settings.
Chrome
Advanced Settings > System > Turn off hardware accelerations
Firefox
Performance > Uncheck "Use recommended serformance settings" > Uncheck "Use hardware acceleration when available"
Then restart your browser.
Or you could try to reset NVRAM or PRAM.
Hope this helps!