Proxmox is really popular with both people having some kind of home server, but also with companies renting bare metal servers. It's a viable alternative to XCP-ng and VMware, for instance. I'm going to use mine for some minor services, but mainly as a testing rig to learn more about both Proxmox itself as well as projects I'm curious about.

As a freelancer it's important to have some kind of environment to test things on, as it's not so common that the companies I work for can provide that. I splurged and got myself a new ZBOX-CI337NANO N100. I usually prefer trying to stick to used hardware, but having a reasonably strong little server that consumes little energy and has passive cooling felt important. I put in 32 GB of RAM and 512 GB of storage.