I’m not familiar with the Ben Eater series, but there are certainly a couple options to check out.

Mark Ferneaux did a fantastic series on the workings of pfSense. It’s a little dated, but the core concepts are still sound and apply to networking generally.

There are also several sites that do in-depth networking topics with a focus on certifications. My favorite of the bunch is Viatto.

I also quite like The Network Berg, though his videos are specifically focused on Mikrotik.

The thing that immediately came to mind was mailpiler.org. It’s been on my list to stand up for a while, but I’ve never got around to it.

Awesome. I’m glad it helps. I’d be a little weary of using the same directory in multiple containers. File systems may or may not behave well with multiple machines writing to them. Not saying anything bad will happen, but do keep an eye out for issues.

I’m making some assumptions, namely that you’re using an unprivileged LXC container and the mount point is a bind mount.

Unprivileged LXC shift user ID numbers so that an escape won’t result in root access to the host. The root user (uid 0) in the container is actually uid 100000 from the perspective of the Proxmox host.

What I usually do is set ownership of my bind mounts to that high-numbered ID (so something like chown -R 100000:100000 /path/to/bind/mount) from Proxmox. Then the root user in the container will be able to set whatever permissions you need directly.

Check out ersatztv.org. That software lefts you create custom, continuously playing channels that you can watch from Jellyfin as a live TV channel.