Maybe give this a try https://addons.mozilla.org/en-US/firefox/addon/containers-with-transitions/ https://addons.mozilla.org/en-US/firefox/addon/containers-wi..

Maybe give this a try https://addons.mozilla.org/en-US/firefox/addon/containers-with-transitions/ https://addons.mozilla.org/en-US/firefox/addon/containers-wi... (source, i haven't looked: https://github.com/blackhole89/multi-account-containers https://github.com/blackhole89/multi-account-containers)