is it profittable to open a server now?

About selling:

Its hard to get donations if youre having a legal server that follows the EULA.

The EULA are the rules of a server set by Mojang. Its says that youre not allowed to sell ingame advantages..
this being said, why would you pay 10$ for the prefix [vip] or why would you pay for some trails etc.
it only allows server owners to sell cosmetics (and its never worth buying cosmetics)
So you would have to find a way to still sell ingame advantages without breaking the EULA


About the players:

I found why players don't come back to small servers -> players come to players, no players on youre server? noone will come.
So i suggest you trying to make youre server only be avaible in weekends, so the playerbase has to join in a small period.. (so they will Always see eachother)

Also, friends help.. having about 5 irl friends playing minecraft won't make it.. you would easily need 20+ friends that are active on minecraft & youre server.
That being said -> give them helper rank or something, (not all of them because if there are like 20 players online, all 20 helpers.. is strange)
because they are "helper" they feel important and be online and check if everything works.. They will most likely tell their friends that they got the staff rank at youre server and want their friends to play there
so they can show it to them..


So i think having friends is needed to start a server (so it won't be dead in the first week)