After a single APT command gone wrong made my Debian installation unusable, I decided to reinstall Linux. I tried to back up everything to my external hard drive, but it kept unmounting, so I elected to use Filen (a FOSS cloud storage provider) instead.
It was only after installing openSUSE Tumbleweed with KDE Plasma that I realised I hadn’t actually synchronised the folder I had moved my backup to; meaning I have lost everything but a single Minecraft world (which I had backed up to a Compact Flash card in February).
Tl;dr: Double check your backups, and use physical storage whenever possible.
Sorry about your data loss.
I self host an instance of nextcloud on a headless machine in my home. It gives the benefits of typical cloud based services, but you control the storage. And if you sync with at least one other machine you have a full backup besides.
Of course no solution is perfect. This requires extra time, effort, and hardware. And having my data in one physical location has it’s own risks. But I still prefer it.
So, something to consider if you or whoever is reading this isn’t aware of that option.