For what you’re describing (Immich, Navidrome, Jellyfin, Nextcloud), you don’t necessarily need to figure out drive redundancy and server builds from scratch.

Take a look at Syncloud — it’s fully open source and lets you install apps like Nextcloud, Jellyfin, and more from a simple app store. It handles storage, HTTPS, and updates for you. Runs on pretty much anything — an old PC, a mini server, even a Raspberry Pi. Might save you a lot of the confusion around where to start.