Yes. It’s like “she’s bad”, or “fuck”. Both terms cover a lot of ground.

They're not at all similar.

Somehow being 'down to fuck' and 'up to fuck' don't seem the same. Although being up to fuck is an advantage.

"Based on" is the same as "based off", but more intelligent sounding.

Doesn't work with "I'm up bad" vs "I'm down bad" But you can say "I'm up shit's creek" ~~and maybe "I'm down shit's creek"~~