I’m curious to know more about your “certain date” requirement - this sounds like it might be an XY problem. As for general advanced backup programs, I have two easy recommendations that are similar in featureset:

• Vorta (based on Borg)
• Kopia

The most important parts of real backup software IMO is the ability to compress your backups, version your files with rolling/pruning snapshots, and version your files efficiently with only deltas between them taking extra space. You can also encrypt your backup if you want to store it with a remote party, or run integrity checks to check for bitrot.

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 like restic, haven’t seen it mentioned yet.

Pika Backup. It’s very easy to use, you select the directories you want to backup and the ones you want to exclude, then your job is over. Every time you ask it to backup it will add the new and changed files to the backup without deleting the old ones. This way the backups only grow with what’s changed.

You can also ask Pika to schedule automatic backups, or you can ask for one manually if the USB HDD is not plugged in all the time.

I’m using borg with vorta as a front-end, which seems to work quite well, with different possible backup targets

i use rdiff-backup

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

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.