Install proxmox on a computer with plenty of RAM and CPU and you’ll be able to create VMs which you can give out or rent out to anyone.

In regards to access, ipv4 is not a good idea, and you should get a lot of ipv6 addresses. But anyways, first you need the server with the hypervisor (which is what you’re looking for) and then you can slowly run tests, learn and eventually figure out networking.

Btw, it might be cheaper to simply rent a server, which would solve the issue of ip addresses. OVH has cheap servers and a proxmox install wizard.

Just please don’t use it for anything sensitive until you can find someone to give a quick check up in regards to security to make sure you haven’t missed anything. Unlike a regular PC at home this one is expected to receive inbound corrections which has its risks.