I’ve been using ViewTube specifically because it was easier to set up. Although it also fails to play videos occasionally

I’m doing basically all the things you’ve just listed using a Dell Precision Tower 3620 you don’t necessarily need new hardware for it and could save quite a lot if there are used workstations in your area.

For software I’m using esxi with truenas core virtualized and photonos as my docker host with everything managed through portainer. I would not suggest using esxi unless you want to learn about it, I wish I’d gone with Proxmox at the start.