Use timeshift, install it, just chose where you want the backups to be installed, preferably a second HD or SD Flash. Chose when like once a day, week at start up for instance and forget it. Then if you screw up your Linux, just start in console mode, timeshift --restore and five mins later your up and running.

If you want just your data to be copied, then Cron

Both are standard Linux programs, often already installed depending on what Linux you have

I use a service called iCloud which has both cloud storage and local backup support built into it. Not free or open source but no cloud platform fully is. It’s also really cheap for students.

i use rdiff-backup

https://github.com/rdiff-backup/rdiff-backup

I use Borg to my nas, then rclone that to rsync.net. With Borg if you need the remote copy, you can interact with it directly.

You can, of course, Borg directly to rsync.net. You can also use rsync instead and let their ZFS snapshots do retention for you.