I want to achieve this without a plugin

Why? I would say that's the job of a plugin.

And, by the way, I don't see a reliable way to check if a user just forgot to log out correctly. Then the log in from another computer/browser will be blocked at least until the next session timeout. Maybe longer.

And please describe a common use case for this issue. I can't imagine one.

And please describe a common use case for this issue. I can't imagine one.

such thing often used on paid/per subscription services

I don't see a reliable way to check if a user just forgot to log out correctly

that easy, when user logged in then all existing session for same user "logout"

I think it a job for a plugin developer.

that easy, when user logged in then all existing session for same user "logout"

Yes, that's easy. Kicking all logged in users out if somebody tries to login with same credentials/userId.
But @MauriceTerer said:

so that a user cant login using another computer or browser when already logged in.

then I misunderstood

It has been more than one month since the request for more information from the original poster without reply. I am closing this. It can always be reopened if required.