The next Lemmy version will add a donation dialog, which is shown once a year to every user, in order to increase the amount of donations for Lemmy development. You can see the current text in the screenshot above and in the translations repo. You can also checkout the frontend PR. Is there anything you would change about the text?
Imho the best would be one that is customizable by the instance admins.
You mean to add donation links for the instance? That makes sense, but I fear that it would be too complicated for users. Admins already have many ways to put donation links eg in the sidebar and sticky posts, but for developers theres only a small button at the top which is easy to miss. And our donations have gone down a lot, now only 2400 Euro per month.
Well, I think a personalized message (maybe in the primary language of the instance) is more effective than some standard text thats everywhere.
I think most instance admins realize that there is also a need to support the devs, and a single place that advertises both and can get linked from the sidebar might also be more bring more donations to the devs.