Mozilla is basically a not-for-profit/for-profit that protects/violates your privacy.
I don’t understand why some people are confused. It’s really quite simple.
Try librewolf. Its just like firefox, but without all the bad stuff (and a great community too) - https://fosstodon.org/@futureisfoss/106168706827904386
Or live with every major website (and Mastodon's web UI, etc) being broken.
I'd probably recommend something some WebKit (Apple, with others)-based browser: GNOME Web, Midori, etc.
The social network of the future: No ads, no corporate surveillance, ethical design, and decentralization! Own your data with Mastodon!