As everything I found regarding this topic is not solving my issue I'm requesting this here again (the only two similar posts are a year old and not solved soo)

What I want is r.g. having two tabs of google mail open, one is logged in with my work account, the other is logged in with my private account.

(Just look at multi account containers extension for firefox and you'll get the point)

No, profiles is not a solution, sadly.

But if anyone has any workaroud/add-on that works like that I'd really appreciate if you send it my way

In the meantime, any dev, also add-on devs, please have mercy and create this