I think the best thing to do right now is to increase the active user count, then worry about conversion rate (basically percentage of users who contribute, which seems not good enough for lemmy)

e.g. fosstodon has about 42,934 MAU and makes about $3,236 (about 13 users per dollar).

for mastodon it's 2706053 MAU and makes about $33,627 (about 80 users per dollar).

for lemmy it seems like it's 7.6 users per dollar , but i think that could be higher because the donate button seems almost invisible.