... I usually have 3-4 browsers open (Firefox, Chrome, Brave, and Opera), and have segmented my internet experience in that way, just because I can. If something seems wrong in the display of a site, I can switch to another browser very quickly and see what's up. Obviously I am an oddball in that regard.
I use FF exclusively and have it locked down via its security features plus AdblockPlus and Ghostery, so from time to time I will see missing videos, etc. At that point, if I car enough, I will open plain vanilla Edge or Chrome.
FWIW here is my full tweeks list:
FF keep from jumping to the new tab after I click a bookmark about:config "browser.tabs.loadInBackground" to true
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FF keep from jumping to the new tab after I click a link about:config "browser.tabs.loadBookmarksInBackground" to true
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FF keep from jumping to the new tab after I click a link on a page about:config "browser.tabs.loadDivertedInBackground" to true
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FF keep from closing when closing last tab: about:config set the browser.tabs.closeWindowWithLastTab to false
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FF suppress double line feeds in forum posts: about:config "editor.use_div_for_default_newlines" make it false.
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FF Open searches in new tab, about:config set browser.search.openintab to true
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FF open new tab from address bar: about:config browser.urlbar.openintab to true
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These set up FF to my taste. Obviously YMMV.