OS crashed "CommCenter wants to use the keychain 'session'"

Hello,

Since yesterday my Mac (MBP 2019, OS Big Sur) is completely frozen as follows:

• It’s extremely slow
• Multiple windows saying "Commcenter wants to use the 'session' keychain, please enter your password" = Entering the password doesn't change anything
• Cannot click on the Apple menu (so impossible to shut down or restart) = Even after relaunching the Finder
• Cannot launch any application, including Activity Monitor and the Terminal to try to type a shutdown command...
• Moreover, since this is an EXTRAORDINARY MBP 2019, I don't have a physical power or eject button (Touch Bar, a great invention), I’ve already tried multiple key combinations without success (is there a keyboard command to force a restart without a power/eject button??)
• It’s overheating, so hot that it’s burning and I can't touch it

The only thing I can do is close it to put it to sleep and stop it from heating up
=> A solution for:
1°) restarting it?? It's incredible not to be able to shut it down... I’m about to open it to disconnect the battery..........
2°) resolving this keychain 'session' issue?

Thank you in advance.

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