typically you only need one power supply to run it, once you move to redundant power you can use the second one in case the first one fails. when you plug both in it will just balance across both until one fails.

in my opinion, hardware should only be hypervisors that run virtual machines, then you can provision VMs, similar to using VPSs. going this route you will need a vga monitor for initial setup, eventually everything is done over the lan with a web ui or ssh.

i use proxmox which is Debian based for the hypervisor.

As far as what you do with it, is that you can in theory replace the VPSs or test software in your lan.

to compare, i have my router (vyos), homeassistant, a docker server for hosting small services, a network lab (gns3), windows and mac VMs, and more running on a cluster that is using similar hardware.

it looks like there is a bedrock branch, but i personally have no experience with bedrock.

see this issue for more details: https://github.com/minekube/gate/issues/11

i have used gate for my internal and external, works very well and i do exactly what you are asking and separate different versions and modpacks by name https://github.com/minekube/gate

everything should be behind a firewall