More than fair. I do have a Proxmoxy solution if you want it, which is to run it as an LXC, but it does seem that something more container-oriented may be your best bet rather than sticking with proxmox if you don't need the extra stuff it offers.
Here's an absolutely incredible resource when it comes to home running Proxmox LXCs: https://tteck.github.io/Proxmox/
Pihole is offered (spelled Pi-hole), as well as a ton of other useful services.
Proxmox doesn't really do Docker containers well (yet, or maybe will at all). It does do LXC (both of those are OCI containers at heart), but that's not as well supported or as versatile as Docker/Podman. I'm more than sure Unraid is great at what it does, but it's not a VMWare killing virtualization solution in production like Proxmox is with its great support for redundancy, versatility and relative ease of use if you come from a Linux background. OTOH Proxmox is not Portainer. It's for VMs and VM-like containers, at least for now. Supposedly kernel 6.something helps a lot with OverlayFS support in nested containers, but I can't go to bleeding edge kernels in production to test that. Still, are you sure you need an IP per container?
Round peg, square hole IMO. Discord is designed as a chat application with an afterthought of threading and forums (I guess?). It's not a reddit replacement, and it's not designed as a forum.