This donation link currently takes you to a page that appears to be for donations for Mastodon. While I understand that you may be also running servers for Mastodon, Lemmy is a separate entity, and, as such, I believe its donations should be kept separate. When a user donates, I would wager that they don’t want to feel like their donation may be used for a separate service that they may or may not use; they would want it to be used for exactly what they donated for.
It is possible that this may not be the case; the donation page name may just be a legacy thing, and not some combined pool of funds. If so, I strongly recommend adding some description to the page stating that that is the case, or better yet, simply rename it to lemmy.world donations.
I think the ideal solution would be for there to be some way to specify whether the donation ought to be specifically for Lemmy.world, specifically for mastodon.world, or be fungible for both.
Some people here don’t necessarily use mastodon.world or vice versa. And some do. Or maybe some don’t care.
Whether specifying such options is feasible… I’m not sure. But it would be nice.