Really depends on what you have, what you're trying to store, etc, etc.
Like we need more info.
I've been running a windows desktop as my "server" for years, with a large data drive, that's backed up by Crashplan.
It stores all our phone stuff - pictures, downloads, app Backups, etc, that get their via Syncthing and Foldersync.
I'm currently in the process of switching to a Raspberry Pi to handle a few things: Tailscale (mesh network), PiHole (for home network), Syncthing. It's data drive (however I decide to do that, direct connected or some kind of NAS) will be backed up to a service like Backblaze B2 or something like it.
The power draw if that desktop is massive compared to the Pi. Granted the Pi lacks horsepower, but it should be fine for what I need it to do.