"As of January 2022, the platform had approximately 40 million monthly active users."[0]
In 2022 they had $30M expenses, so the cost is somewhat under $1/user/year.
They said the minimum donation is there to reduce the viability of scammers using it to check if a stolen credit card number is valid.
Where is this $5.7M coming from? According to their tax filings in 2022, they paid their CEO $0: https://projects.propublica.org/nonprofits/organizations/824506840 (compensation section)
They are paying their CEO $0. Brian Acton, previously founder of WhatsApp, the guy who initially bankrolled the whole non-profit by a $50 million, 50 year, non-secured, 0% interst loan, later giving even more.
Source: https://en.wikipedia.org/wiki/Signal_Foundation#History
They pay some other C levels 400-600k. Source: https://projects.propublica.org/nonprofits/organizations/824506840 (compensation section)
Which site? Choose another instance if yours is unreliable. That's the advantage of a federated system. Or just have a second account at another instance.
There is https://www.goldencheetah.org/
It's mostly for cycling, not too user friendly, not well documented, but very powerful once you figure out how to use it.
I played and enjoyed Chants of Sennaar and Jusant in the last few months. A recent standout game for me was Tunic. Check it out, it might suit you well as much as it did me. It has fighting but if you want you can enable easier combat or even "no fail mode" (invulnerability) from the menu. The game has a ton of hidden secrets and puzzles while being pretty and friendly to look at like the other two games. It is a great experience with or without the combat parts.