It happened to me on Ubuntu. VLC and Jellyfin would both get screen tearing. Games were fine though. After some research, I found that turning on ‘force full composition pipeline’ in the Nvidia settings fixed it. Still too new to understand the how and why.
Fluoride can be bad for you, just at much higher doses than they put in water supply. It can cause issues with bones and neurological development. Again, only in very high doses over a long time. It happens a lot in poorer countries where they can’t treat well water.
https://en.m.wikipedia.org/wiki/Skeletal_fluorosis