I think it's a question of philosophy. If I take donations for something, is it really still my hobby projects I build in my free time?
Not really IMO. The moment I make money off it, it's more than that.
And if I have a community of people who use that project, I should be transparent with them and engage with them. Maybe the Lemmy devs are doing this in some place where I'm not (like on their matrix), but I have never seen them explain why they are working on certain features and not on others. Their development updates are awesome and I appreciate them, but it's very much a communication of "we are doing this, see you next time". The recent AMA was a good example of engagement that gives the possibility to explain things better and get into contact. My advice would be to work on communication and feedback channels.