I use RiMusic and love it. I was using ViMusic, but then it got discontinued and I found RiMusic, which is a fork (and I like it better than the original).

I’m outta here

You could point the DynDNS to your first server, generate a valid SSL certificate with letsencrypt, then move DynDNS and the certificate to the new server.

As per your update, the problem with the server is generating certificates, right?