most trustworthy browser extentions to remove facebook reels, google shorts, etc.?
Not using those sites.
use ublock origin and select the tabs and hide themor find some scripts for greasemonkey on greasyforkfor android there is distraction free Instagram and newpipe
https://addons.mozilla.org/en/firefox/addon/youtube-shorts-block/ turns shorts into regualr videoshttps://addons.mozilla.org/en/firefox/addon/antireels removes them