I have the opposite problem. I regularly open lots of tabs, and Chrome just expands its real estate pushing things into swap. Firefox just chugs on like a champion.
Definitely the opposite of what I see, as well.
The RAM think really depends on the websites and what resources they are allocating. The browser is really just accommodate that. Sites that do continuous scroll are the worst as they often don’t release resources as they go.
Firefox is a colossal RAM guzzler.