I’d recommend building your own server rather than buying an off-the-shelf NAS. The NAS will have limited upgrade options - usually, if you want to make it more powerful in the future, you’ll have to buy a new one. If you build your own, you can freely upgrade it in the future - add more memory (RAM), make it faster by replacing the CPU with a better one, etc.

If you want a small one, the Asus Prime AP201 is a pretty nice (and affordable!) case.

I run a couple of containers on my lenovo mini pc. I have proxmox installed on bare metal and then one VM for truenas, one for docker containers and one for home assistant OS.

For me the limiting factor is definitely RAM. I have 20GB (because the machine came with a 2x4GB configuration and I bought a single 16GB upgrade stick) and am constantly at ~98% utilization.

To be fair, about half of that is eaten up by TrueNAS alone due to ZFS.

The point I’m trying to make is basically make sure you can put enough RAM into your machine. Some NAS have soldered memory you won’t be able to upgrade. The CPU performance you need highly depends on what you want to do.

In my case the only CPU intensive task I have is media transcoding which can often be offloaded to dedicated bardware like intel quicksync. The only annoying exception is hardware transcoding of x265 media which is apparently only supported from intel 7th gen and upwards processors and I have a 6th gen i5… Or maybe I configured something wrong. No clue

Edit: I wrote that after reading the first half of your comment. Regarding connecting a screen, I think I had one connected once to set up proxmox. Afterwards I just log into the proxmox web interface. If required I can use that to get a GUI session of each VM as well.

I moved from lxc to docker. Much easier to manage.

I personally prefer Docker over LXC since the containers are essentially immutable. You can completely delete and recreate a container without causing issues. All your data is stored outside the container in a Docker volume, so deleting the container doesn’t delete your volume. Your docker-compose describes the exact state of the containers (as long as you use version numbers rather than tags like latest)

Good Docker containers are “distroless” which means it only contains the app and the bare minimum dependencies for the app to run, without any extraneous OS stuff in it. LXC containers aren’t as light since as far as I know they always contain an OS.