Use qemu, or proxmox (it includes qemu).

Create one VM to your liking, then make it a template.

So when you need a new VM, you clone the template, and that’s it.

if you match your usage to the UPS exactly, your runtime will be zero

No, it will be 1 exactly.

But what is the unit of 1? Minutes? Seconds, Hours? That’s what’s missing in the OP

Besides ansible, also have a look at “templates” and “cloud-init” for VM generation.

The biggest issue is that the app and recommendation algorithm isn’t going to be useful with 20 songs.

They are not testing for usefulness.

If your basic logic runs with 5 songs, then give them 5, not 20.

Nextcloud…

don’t want your server maxing out all day

But don’t you think about that poor server?

It is feeling so bored out and it’s whole life worthless…

What the … LOL

They are prepared for such ideas, and you should assume that they are better than you.