[2022] Very serious multiplayer issues

I'm not aware this is a general problem. Are you on the Steam edition of the game, or a different one?

If the Steam one are you using crossplay to play MP?  

Yet I see nothing like this in the MP forum here, several ongoing games there in fact.

Is this just when you are involved , can the other players all play together without you okay?

Do you have any ability to test this from a different location/internet connection?  

In no way am I suggesting you do not have this problem.

But for this to be reported to the developers it needs to be able to be duplicated by QA and/or them. I'm trying to establish the scope of the issue here; if indeed it only happens when you are involved then it seems very likely it is not a general game bug, but some local issue. That said, the tests you have now done (thank you for that!) ought to have come out differently if that were so!

Is there any way you can try from a different location, on a different machine?

If you believe it is your Paradox account, can you make a second one with a different email, as a test?  

Is your machine an ASUS? If so they can have an MP 'helper' app (which we do not name in public) which crashes others' MP sessions, even computers.