You don't even need a hacked version. Just use an older version. Besides, Firefox is open source, I'm sure someone would fork off an adblock allowed version.
I have a 3080 and the game runs noticeably worse in the cities than it does in small rooms. And that's with everything at low-medium and 75% rendering resolution which seems ridiculous. And the game doesn't even look that good.
It's reasonable to expect high framerates in 2023. If people want the game to run smooth there's nothing wrong with that. Hell, doom eternal was a Bethesda game and it looked gorgeous and ran like butter, so we know they can pull it off.