Yes I think it would make very little difference indeed.
From what I understand you don’t have administrator rights on the network on which you want to implement your pi. Only your administrator will be able to set up a DMZ, a separate subnet, or any other solution to isolate your pi from the rest of the network, as well as to forward the ports necessary for the proper functioning of YunoHost. You should see with him what is possible or not.
If you have the motivation to deploy a self-made one, you can get away with it for less than $20 a year.