They didn’t provide an rsync example until later in the post, the comment about not supporting differential backups is in reference to using rsync itself, which is incorrect, because rsync does support differential backups.

I agree with you that not doing differential backups is a problem, I’m simply commenting that this is not a drawback of using rsync, it’s an implementation problem on the user’s part. It would be like somebody saying “I like my Rav4, it’s just problematic because I don’t go to the grocery store with it” and someone else saying “that’s a big drawback, the grocery store has a lot of important items and you need to be able to go to it”. While true, it’s based on a faulty premise, because of course a Rav4 can go to the grocery store like any other car, it’s a non-issue to begin with. OP just needs to fix their backup script to start doing differential backups.

My KVM hosts use “virsh backup begin” to make full backups nightly.

All machines, including the KVM hosts and laptops, use rsync with --link-dest to create daily incremental versioned backups on my main backup server.

The main backup server pushes client-side encrypted backups which include the latest daily snapshot for every system to rsync.net via Borg.

I also have 2 DASs with 2 22TB encrypted drives in each. One of these is plugged into the backup server while the other one sits powered off in a drawer in my desk at work. The main backup server pushes all backups to this DAS weekly and I swap the two DASs ~monthly so the one in my desk at work is never more than a month or so out of date.

It’s not a drawback because rsync has supported incremental versioned backups for over a decade, you just have to use the flag and add a couple lines of code around it for management.

Dual booting is not a great long-term plan because it’s updates are known to delete grub

That problem is overblown. I’ve been dual-booting Windows and Linux for around 20 years now, I think I’ve had that happen…once? Over a decade ago? And to fix it you just use a Linux live USB to boot back in and repair grub. People bring it up every time dual-booting is mentioned as if it’s the end of the world, but in reality it’s a very rare problem and is easy to fix if it happens.