Use docker compose . Like “everyone” uses it. If the service doesn’t have a compose file, request it, or write it yourself as son as you are knowledgable enough.

Use podman as soon as people and services switch to it (you’ll know when the latest tutorials talk about podman instead of docker).

Use ngingx proxy manager or another easy to use reverse proxy.

Don’t think it’s production ready after it was working 2 days. It may be, but it’s unlikely you have enough knowledge how to fix things.

Automatic updates.

Don’t install crap on the system.

Start with hardware you have already, its high likely overkill anyway. If you have CPU that supports quicksync (intel 7th gen or newer iirc) you could remove GPU to reduce power consumption. QuickSync will make streaming easy.

Raspberry pi cant transcode so its not best for media server, but it can direct play so that might not be an issue at all. I upgraded from rpi to desktop PC because I had issues with power on rpi USB ports for storage. Its also impossible to upgrade RAM on rpi. Good thing about rpi is super low power consuption, but some small factor PCs can drain ~10W. My PC was at 22W with 3 SSD. You can get power meter like Shelly plug S to see power consuption yourself.

Any OS (I use debian) of your choice + docker and docker-compose. Then install portainer and manage all services from there.

• For pictures try Immich, its amazing.
• For cloud storage Nextcloud
• For media streaming consider Jellyfin (much better than Plex IMO)
• Check wiki.servarr.com if you are downloading content with torrents or usenet. It can automate everything and provide awesome UI for users. Next level torrenting
• If you have only 1-2 users consider Wireguard or tailscale to connect when not at home.

I was going this route and Im super happy with everything

Whatever you do:

• keep notes
• consider the 1st build “wrong”
• “destroy” it (before it’s the only place your data is stored in)
• build it again

That means you’ll really understand it and how to maintain it.

And others have said: 3-2-1 backups

For a privacy friendly OS, surprised nobody has mentioned Freedombox

It’s designed explicitly for your use case, along with an easy path to other self hosted services. When you’re ready for more than it offers through the web interface, it’s a full Debian install under the hood - so you can install whatever you need to. Privacy friendly and super stable, with smooth upgrades to new releases and security updates for old versions several years after the new one is available.

As far as hardware, your old computer is probably more powerful than a Pi and can support more drives, but the Pi will be more power efficient. As others have mentioned, if you care about your data long term then backups are a must, so a separate NAS or a Pi with a large drive for backup storage is a good idea as well, whatever OS you choose.