did you maybe touch the ui scaling? it doesn't always play nice with othersFirefox, Chrome, and even Edge on occasion. Edge was where it kept crashing, but even on the others I still have trouble watching videos unless I use fullscreen on them (at normal size they lose quality and buffer like crazy). Aside from that the browser doesn't really matter, I still have to fullscreen the browser and/or use the "Shrink UI" option in Regalia to see all of the options. I don't recall changing anything on my computer other than my resolution, but even changing it to smaller resolutions doesn't seem to change anything.
if not maybe consider doing a fresh install of windows. i know it's a pain in the ass but from an idiot that spent many, many hours over several days to find the problem and fix the system, it's faster to just do a fresh install and it usually fixes any problem(rare exceptions) unless it's hardware (and at least then you know)