I’d recommend finding a tutorial for Docker+Portainer - Portainer is a container as well, which provides a web-gui to conveniently manage all your other containers (without having to touch the CLI ever again)

The Hacs Integration makes use of the device’s API - don’t know if it is their intended use of it, but it works

You can turn off the internet access at almost all Tuya devices by making use of the local tuya HACS add on in home assistant. Maybe that’s helpful for your research

Don’t worry, most of this is about learning :) You could also put Docker on the Linux, install Jellyfin as a Docker container, and only fore it up when you are using Jellyfin. It’s a little less convenient, than having it available all the time, but storing all media in H264 AC3 (most common video and audio codecs) costs a lot of storage (H265 and AV1 are far more efficient). Another pro of Docker is, when you decide to move your server, you just shut down the container, copy it’s data and start the container on the new device

You’ll have to keep in mind, that the pi is not really suitable for RAID and not at all for transcoding. The latter means if you have all your media in codecs your devices support, it’s direct play only, it will work, but as soon as you need to transcode, you will have a hard time

I’d go for the consumer case with as much drive space as possible, but in the end it’s up to your taste. With rackmount full professional server stuff, you have to keep in mind, it’s not only quite large in terms of space, but also noisy. This is something for the basement or something. Another option would be a mini pc like a NUC combined with a NAS - here is the limit the upgradability of the hardware. Like you can usually upgrade the RAM a little and the system drive, but that’s it. Especially for media stuff (Plex, Emby, Jellyfin) it can be interesting to have a dedicated GPU, like an Intel card, to have more transcoding capabilities. I’m currently running most things from a SFF PC, but also have a Pi and an old laptop in use for various tasks (main reason is lazyness to move the services to the SFF lol)

That’s the good thing about containers, that’s super easy. Just stop the container, move your folder to your desired location (e.g. /home/user/vaultwarden), change the path in your compose file (stack) (i.e.: /home/user/vaultwarden:/data/), redeploy the stack and that’s it :)

Since you already got a lot of ELI5s, here is a basic to-do to get you up and running. From my experience, since I use the exact same setup as you describe.

1. Set up your containers in a way you can reach them from you local network (e.g. http://123.456.789.10:123)
2. Get a domain name (you can get one at the registrar of your choice, e.g. mydomain.com)
3. Set up NGINX proxy manager (NPM) (default address of webui would be http://123.456.789.10:81)
4. Set up a new proxy host in NPM:
   • Domain name: mycontainer.mydomain.com
   • Scheme: http
   • Forward Hostname/IP: 123.456.789.10 (if you get an error later on, you can use the docker container name if NPM and your container are connected to the same Docker network)
   • Port: 123
   • Via access lists you can provide a very basic username/pw login to protect your sites (you can do more and cooler stuff with Authelia)
   • In the SSL tab you can (and should) setup the SSL encryption: https://www.youtube.com/watch?v=TBGOJA27m_0
5. Go to the DNS management of your registrar
   • Add an A-record for mydomain.com and the public IP of your server (you can google public IP to find it out)
   • Add a CNAME record for the subdomain with name mycontainer and target mydomain.com
6. open port 443 of your server in your router If everything worked right, you can visit mycontainer.mydomain.com, your DNS server will resolve this to your public IP and forwards the request to nginx, which will serve the data of your local container