In Windows 10 I have shortcuts pinned to my taskbar that are just

> ...firefox.exe" -P "profilename"

and then `taskbar.grouping.useprofile true` so only windows from the same profile are grouped together and some custom recolored Firefox icons for those pinned shortcuts and custom per-profile userChrome.css styling (#TabsToolbar background-color) for easy visual differentiation of a window's profile.

For Windows 10, no scripting is needed. Just the initial GUI profile setup.

> ...firefox.exe" -P "profilename" "https://www.example.com"

from terminal works exactly as expected regardless of how many profile instances are currently running or their state.

You can even have multiple versions of Firefox installed and point them at different profiles. I have some profiles on ESR and some on Standard.

>from terminal [opening URLs in instances using profile paths] works exactly as expected regardless of how many profile instances are currently running or their state.

That's interesting. It didn't work a couple of years ago, perhaps it's been fixed.

Still leaves that initial GUI profile setup.

Cannot get this to work with Win11, whose taskbar won't accept the same program pinned twice. Even not, after creating two shortcuts.

I do this on Linux (Mint) and it works as expected.