Since the last update (Firefox 100), the scrollbar in Firefox fades out slowly when you don't move the mouse for a second and immediately reappears when the mouse moves one pixel. This drives me nuts as something moves on the side of text inputs or the page whenever I am trying to read something. I looked for it but found only old posts like this support article and this superuser question that don't seem relevant.
How can this behavior be disabled? Surely there's a preference for something as annoying as this?