I did exactly this same thing a few years ago. First, I backed up the data in my (unhidden) /home folders and my Firefox bookmarks, settings, etc.. Then, using a gparted live disk, I
That was it. It worked fine; it booted fine. I acknowledge something could've gone wrong, but since---like you---I was willing to re-install Linux if necessary, I was comfortable with the risk.
Regarding VMs, I have an only casual experience with them. I used Oracle's Virtualbox for years, but lately I've become fond of Gnome's Boxes. Google either of those and you'll find tons of guidance on usage. :)
Well, kind of. GNOME Boxes is actually a new, designed in a Gnome 3 style, GUI for KVM.
"While virt-manager does a very good job as a virtual machine management software, its very much tailored for system administration and virtual machines. Boxes on the other hand is targeted towards typical desktop end-user who either just want a very safe and easy way to try out new operating systems or new (potentially unstable) versions of her/his favorite operating system(s), or need to connect to a remote machine (home-office connection being a typical use-case). For this reason, Boxes will not provide many of the advanced options to tweak virtual machines provided by virt-manager. Instead Boxes will focus on getting things working out of the box with very little input from user. " https://wiki.gnome.org/action/show/Apps/Boxes