Well thats what backups are for, but may be start with a mirror or with unimportant stuff for at least a year ;) Also proprietary service can delete your data, too. This happens especially when you are using the generous free tier and they decide to make more money. See Evernote, Gitlab, Heroku…
It is also very resource efficient. I am running it on a Raspberry Pi 2 and it works flawlessly.
I use a Raspberry Pi 2 to self host a Dashboard written in Rust (Axum), a RSS reader called yarr and a music streaming server Navidrome. The latter two are written in Go and very resource efficient. The electricity bill should be under a Euro a month (6.4W max power consumption).
I‘ve recently started using Tailscale for my home setup and I really can‘t recommend it enough. In my opinion it takes a lot of the dangers regarding IT security out of self hosting. Depending on who you ask it is not true self hosting, but I couldn’t care less :)
With Tailscale you can create a VPN for your devices including your phone and even expose services to the outside world with SSL already setup (havent tried that out, yet)
They have guides/tutorials for a lot of stuff (web server, Minecraft).
I chose Navidrome, with which you can stream music from your hard drive. It has very easy setup and it feels just great to stream your own music. I use Tailscale to connect the server to my phone and Ampery as an iOS app.