That's still a lot of resources open to me but my rig is old.
I use this system monitor tool a lot and I have a theory that ANY browser will sink its teeth into the system with content and extensions and not let go and gradually and dramatically increase over the course of hours even if you haven't tabbed much. Even if you kill tabs.
Then a restart makes it right.
I also forget we grant extensions the same admin privileges we enjoy, too, which makes me uneasy as I type it out here...
Long story short: I go thru the same thing. I wonder what I can control in about:config? another day🙂