How about a second server?

Is it possible to have a 2nd YH server, running on the same IP?

The reason is that I have one huge website for which I would like to have a dedicated server.

I think the correct answer is “no but yes”
A YunoHost server expect to have it’s own IP, and needs it to generate https certificates for exemple.

But if the second server is only to host a site, or anything in fact, you can always use the redirect app on the front server to reach the second.

This app is quite light, but 100% of the packets going to the second server will be handled by the frontal (which will also manage the https with real certificases, the second one will only be able to use auto-signed, or rome you genirated and put in)