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 different mediums (hard drives, "cloud", Blu-rays, tape, etc), 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.

on my CachyOS/Arch and NixOS machines I just use borg to backup to my dedicated server. Very easy to do. I have a couple alias' set up so I can view my backups easily through my file manager on whatever local machine. Essentially all you have to do is make a script to tell it what files/folders to backup, what to potentially ignore, how often you want to backup, the time of day you want it to happen, can also tell it to delete old backups. In NixOS it's painfully easy to set up and can be done within the configuration.nix. On other distros the only difference is you have to set up a service and timer for it.

but I like it, it's straight forward, never had issues with it.