The tildes model (though invite only) seems appealing … here is a breakdown of their costs and donations:

https://tildes.net/financials

and on tildes potential lack of funding

What if you don’t get enough donations to run the site full-time?

One of the best parts about avoiding venture capital and other forms of investment is that there’s no pressure. Tildes doesn’t have to reach certain thresholds of traffic or revenue to prevent shutting down. The worst case is just that I end up running Tildes as a side project, and hope that it eventually grows to a point where it’s sustainable to work on full-time.

granted, one main goal for lemmy is federation so approaches may vary, but in any event an influencers sheeple eyeballs revenue VC model is not the only one