@ricci Chromium supports this incredibly smoothly. Allowing me to just open a client's 'browser' when I need it. All things for that client saved in that new screen. Running next to my 'personal' browser. And close it when I'm done.
Ff profiles kinda do this, but it is a very barebones experience, and because of some bug somewhere, if I have multiple profiles open, after a while the connection dies and I have to relaunch everything to restore it.