If I backed up my system every time I removed or installed an LO package I wouldn’t have time to do anything else. I’ve done this half dozen times in one day for different testing. One command to remove, one to install. Got over a dozen different versions sitting around. Don’t know why you had a hard time finding instructions, they’re posted in multiple spots. Found multiple right now in a quick search.
As far as actual backups, I used many products (mostly freeware) over the years and Linux is much easier to back/restore than some other OS’s. Wouldn’t touch USB - don’t even have one. Boot right from CD or DVD - currently Clonezilla. Backups & restore quick & simple. Have $20 (after rebate) 3-slot removable rack and just slip in another drive for the backup storage. Pull it out when done and store it (also have USB external docking station - US $10 on sale). These devices also good for cloning. A backup isn’t very good if you have it on the same drive you just backed up. I’ve had drives go completely dead.
You also learn that even if people take some kind of backup (which most don’t until it’s too late), it isn’t stored properly anyway. Ask a person if they take backups. If they say yes, ask where they put the backup. 99% will say in the desk drawer. Now, what happens if there is a fire, theft, water damage etc. Lot of good it does. Decades of trying to help people and they don’t pay attention until it’s too late anyway.
BTW - Tried Debian just for the heck of it (already half dozen different Linux flavors) and sorry to say this, but it was the worst at installation, was slow and frankly outdated as far as the Kernel and a variety of other things. Little and no support for many devices older or newer.
It is good to have some instructions logged somewhere (glanced at yours - looks like a pain just for a USB) and I commend you for detailing some. Unfortunately, searching the net now produces many variations on how to do something - some good and some very bad. The problem is weeding out the bad.
Sorry for ranting. The only reason I posted this was I DON’T see a reason to back up a system just to upgrade a piece of software, especially if system backups are taken on a regular basis.