they have to reinvest most of them into the company and it’s employees.
In theory, this would be true. But in Mozilla’s case, “reinvesting into its employees” means giving the CEO a pay raise in the same year they did huge layoffs. They may be not-for-profit on paper, but the actions from their execs are exactly the same as you’d see from any other for-profit corp. Being not-for-profit is just an excuse for shitty business practices and doesn’t change anything in any significant way, imo.
I’m gonna be honest, Mastodon is kinda trash, on its own. It’s clunky, ugly, and feels like a platform from 2010 (but not in a good way). I think getting people onboard with a Misskey/Sharkey instance is going to be much better. The feature set is a lot closer to Twitter, and it does literally everything Mastodon does, but better.