Just open about:profiles. You can create new ones, remove old ones, set which one is the default and can open them in a new browser. I use this all the time t

Just open about:profiles. You can create new ones, remove old ones, set which one is the default and can open them in a new browser. I use this all the time to open a browser as a new SSO functional user without having to log out. I don't know why they don't add this somewhere in the menus and I don't know why you can't bookmark about:profiles, but this works well for me as it is.