Few questions, migth as well just slap em down.

1) Which qbittorrent app is the 'preferred' one? They all look the same to me. And what are Sonarr/Radarr for? I keep seeing people recommend them.

2) Should I bother looking into Wireguard/Tailscale? I don't know jackshit about VPNs, but I don't mind the idea of more security, and even the ability to remote in to my NAS while out. Is there any possibility of giving certain friends of mine access to the NAS as well?

3) Give me a very high level explanation of what Docker really is. Basically like a small-scale VM of just a singular app/OS? Learning about it is on my todo, anyway.

4) Any options/features/etc I should look at in the settings that are good? Since my NAS supports turning back on after a power failure, I've been meaning to move my pi-hole to a VM on it - or is this a case where since it's so lightweight, it'd be better in a docker container?