I’m using Fedora KDE and haven’t set up backups on my desktop PC yet, but on Linux servers (both at home and “in the cloud”) I usually use Borgbackup with Borgmatic. All my systems have two backup destinations: My home server and a storage VPS, both via SSH.

Looks like Pika Backup is a GUI for Borgbackup, so it should be a good choice. Vorta is also popular. GNOME apps tend to focus on simple, easy to use GUIs with minimal customization, so it’s possible Vorta is more configurable. I haven’t tried either.

Don’t forget the 3-2-1 policy: you should have at least three copies of your data, in at least two locations, one of which is off-site (cloud, a NAS at a friend’s or family member’s house, etc). If you’re looking for cloud storage, Hetzner storage boxes are great value. Some VPS providers have good sales (less than $3/TB/month) during Black Friday.