BTW I actually donate to Mozilla because I think it needs to survive

Donations to Mozilla go to the Foundation, not to Mozilla Corp., which is the one developing FF. So you aren't fueling FF development.

Anyway, I've read elsewhere that they're doing fine also without donations: they get 7M$/year in donations and their CEO gets 5M$/year. It doesn't look like they're actually starving...

You may want to think twice before wasting your money:

https://old.reddit.com/r/browsers/comments/yy986k/can_someone_explain_why_mozillas_ceo_salary/

https://en.wikipedia.org/wiki/Mitchell_Baker#Negative_salary-achievements_correlation_controversy

https://techrights.org/o/2022/02/17/mozilla-salaries/

https://news.ycombinator.com/item?id=28116853

https://calpaterson.com/mozilla.html

But it's your money, in the end. Do whatever makes you feel better.