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.
Best luck I’ve had with laptops has been Razer, actually. They’re gaming laptops, so a bit warm and loud and the battery life isn’t great, but they’re built like a brick, can be easily opened, all parts are easily replaceable/upgradeable, and since they generally use Intel everything, Linux compatibility is solid as well (except for RGB lighting and stuff, but with OpenRazer and Polychromatic even that usually works except for brand new models).
My last laptop was a Razer Blade 14 which ran great for like 6 years before I just got bored and decided I wanted to upgrade to a newer model with a better display. Over the 6 years I used it I upgraded the RAM, SSD, added a second SSD, upgraded the WiFi card, etc. It ran literally 24/7 during that entire time other than brief moments when I shut it down to throw in a backpack for travel, the only thing I had to replace for maintenance was the battery. I now have a Razer Blade 16 which has been great for the last year, zero issues, also running 24/7.
Before Razer I used Dell, Lenovo, HP, and Asus. None of them lasted more than 2-3 years before either the plastic crap holding it together fell apart, or the monitor, mouse, or keyboard failed, or I wanted/needed to upgrade something that was not user-replaceable (usually RAM or WiFi).