Backups are usually encrypted from most popular backup programs, either by default or as an option (restic, borg, duplicati, veeam, etc…). So that would take care of someone else getting their hands on your backup data.
I never store my actual files on a cloud service, only encrypted backups.
For local data on my devices, my laptop is encrypted with bitlocker, and my Android phone is by default. My desktop at home is not though.
Have backups. Use something like Veeam Endpoint or a similar software that will image the entire system in a bootable state, and schedule it daily with incremental storage.
Every day stuff could potentially break something, updates out of your control could break something, hardware failures happen, etc…
Yeah the first time was the time/date bug they had (still have?) where it set the time on every folder and file to 00/00/0000 00:00 across all clients and the server.
Second time was I disabled virtual file support on my laptop so it would sync everything, but instead it went and wiped all the files from the server, because for some reason their sync client assumed the laptop that now had no files on it should be the master source or something.
Their own docs even state that’s how you’re supposed to disable VFS, with no mention that it will wipe your server clean.
It’s not open source but I absolutely love Veeam Agent, it will backup an online system with encryption, very easy to use, and they provide a bootable recovery image to restore from.