Interesting. So it's not just me...
Granted, my Win11 (forced in order to use Intuit TurboTax) is strictly VM.
But... And perhaps similar to your Firefox crash, if TurboTax performs an UPDATE, it too does not properly CLOSE and therefore cannot be restarted.
In my case, Task Manager actually gets me back but I have to terminate a WINDOWS INSTALLER PROCESS that TurboTax opened and THEN terminate the unresponsive TurboTax.
So maybe your Firefox opened SOMETHING ELSE and that has to be terminated before you can terminate Firefox ???
Outside of that possibility, if indeed Task Manager cannot get you there, I use System Informer on my host for this type of situation.
I'm using version 3.0.5578 because newer versions do not show my GPU activity properly.
I only use the "release-bin" and never the "release-setup", but that choice is yours.
The NEWER versions are available from here - https://sourceforge.net/projects/systeminformer/files/
The OLDER versions are available from here - sorry, spent about three minutes trying to find, maybe they don't allow them to be downloaded anymore?