(On Windows anyway, don't know if different on Linux)
Just wanted to share that as a user of both Firefox and Chrome, it's one thing that makes me hate switching to Firefox. I often need to use two different profiles and the way Firefox does it sucks.
With Chrome I've got two shortcuts (that Chrome creates by activating an option) pinned to my taskbar that look distinct from one another and the instances that I open are combined under their respective profile shortcuts.
With Firefox I need to manually create two shortcuts, assign two distinct icons to differentiate them, change some properties so they open the right profile, pin them and because they're "regular shortcuts" instead of the default Firefox launcher shortcut, when I open the program I end up with a third Firefox icon in my taskbar (it does not open under the shortcut I used, it acts as if I clicked a shortcut on my desktop) where all instances get merged together no matter which profile they're associated with.
As people have said containers is amazing.
But in the scenario where you really need 2 completely separate browsers and don't want to use different operating system accounts (I've done this in the past).This extension has worked well for me
https://addons.mozilla.org/en-US/firefox/addon/profile-switcher/
It's not ideal that it's an extension but it does do its job
Profile switcher is amazing
Combine with multiaccount container and container proxy, you can manage multi accounts on the same website, control multiple exit gateways VPNs for the same website and completely compartmentalize each type of activity from each other.
Combine that with separate password vaults in each profile and you can greatly tighten your security.
Like I have a banking only profile which has stripped yellow skin and it's the only profile that has access to the password manager with my finance related passwords.
Profile switcher should come out of the box with firefox because installing profile switcher addon and helper program is way too much work for normal people.