Clustering: You could use multiple server to form a cluster over a network. This can be used to migrate and deploy VMs within this cluster and manage them with one webfrontend. I don’t use Proxmox that way, because you need at least 3 machines which are always online and I switch of my PCs when not in use - and I think it works only for VMs without any kind of passthrough.
The Proxmox wiki explains it better than I could: https://pve.proxmox.com/wiki/Cluster_Manager
Mac OS: The RX 5xx series works out of the box and doesn’t require any driver or kernel extension. The RX 6600 needs Lilu.kext and whatevergreen.kext (which is a bunch of workarounds), it came preinstalled with the version of the open core boot loader (boot software which makes Mac OS run on PC hardware) I use, so I opted for the newer GPU.
I heard lots of praise here and there about Proxmox. Personally I don’t have any experience. If you want a GUI, and quickly have something up and running, minimal regular maintenance, I think it won’t be wrong to go with a dedicated distro like Proxmox. Also, if you plan to apply the know-how to work, then it’s the reason to have hands-on on Proxmox or alike.
Personally I run Arch Linux. Always on bleeding edge and so you get features sooner than others. Ideal for home lab purpose. And run QEMU/KVM from command with help of a simple script to orchestrate chores, and manage VMs through SystemD. I find this way I avoid a hell of ‘middle-wares’ that might cause issues: no libvirt, no cockpit, no tonnes of dependent packages to install and maintain.
That’s also a good way to understand how things work under the hood and the know-how is transferrable if you decide to move to Proxmox in future.
You can have a cluster with just two nodes, but I would highly advise against doing a cluster on anything less than 5 nodes (because I got burned by 2 hosts dying unrecoverable deaths). And if you want to launch VMs on a host alone, you’d have to set the quorum votes to 1 and set the cluster down every time. As long as you don’t use HA, you should be fine with 2 hosts and you can migrate VMs between those hosts if you have them as a cluster.
ProxMox is solid and stable. However you can screw things up when configuring PCI passthrough for instance such that the whole thing hangs and you have to reboot That’s not a Proxmox criticism so much as a problem of having all your servers on one bit of hardware.
I would suggest you don’t put your router on ProxMox for that reason, nothing wrong with ProxMox but you want your Internet to work what ever happens.
In terms of ProxMox networking it works fine and can handle multiple ports. The only problem seems to be you need to reboot the whole thing to implement the changes.