I’m not sure I can recommend anything without knowing your goals. For me my needs quickly outgrew my little mini PC and now I have a cluster with a few single board computers. Here’s a basic list of what I run:
Dell workstation (proxmox):
Linux Mint
GPU and USB passed though via Virtio with a sata to USB adapter for connecting the bluray drive
Used as a desktop and is an alternative to my laptop.
It also hosts Jellyfin in a podman container
Docker 0
Nextcloud
TrueNAS
This is a TrueNAS VM with a dedicated sata controller passed though to it. Its used for storage for nextcloud and jellyfin.
Mini PC (proxmox)
landmass
this is a simple LXC container to act as a wireguard client with a caddy proxy. It allows me to access my HDhomerun as it is in another building (long story)
caddy
this used to be for accessing my homerun but is now just for remote access via ssh.
outside access
this is a VM that connects to the VM in linode to route traffic. It runs Ngnix proxy manager and is a wireguard client.
docker1
this hosts Matrix and Drupal. Matrix is basiclly unusable for me because as soon as I start joining rooms the resource usage shoots though the roof and it sometimes crashes
Linode
I have a VM in Linode that routes traffic into outside access via wireguard. It also runs Ngnix proxy manager.
Friendlywrt
I have a Nanopi that acts as a firewall and dhcp server to isolate everything.
This is a incomplete list and doesn’t include my firewall rules or other security measures. I also run Debian on all VMs as it is easy to setup and maintain. If you are looking for somewhere to start I would start by installing nextcloud in a docker container. Proxmox will scale the best but if you are just looking to learn I would install Debian and docker compose. TrueNAS is great for a NAS but its designed to be an appliance so it can be limiting.