LVM is a bit more complicated than just using a normal partition, but it does add a lot of functionality. If you need to make an LVM volume bigger, you can just add another disk to the volume. You can also do RAID like stuff with it. Live resizing of volumes is doable too.
I think some LVM stuff can be done in Disks, but I generally just use the command line. Smarter people, are there graphical LVM utilities I don't know about?
Kinda, yeah. It's an open source but commercial product. The stable releases are paid, the beta is free. I've only been running a three machine cluster for a few months now, but it's been absolutely solid despite power outages, internet outages, a hard drive going pop...
I second the proxmox nomination! I use a fair amount of Ubuntu and Fedora, and with Proxmox, you just spin up whatever you want, whenever you want it. I currently have a machine with a few % of your machine's specs, and I'm running WordPress, jellyfin, pihole, LMDE, and a couple Ubuntu desktops (Mate and Gnome) on different VMs, all at once, like they're running on bare metal.
I had a Tough Book that I had to run a one-liner script on boot so I could have sound. It was something to do with alsamixer. I remember that I couldn't get any audio out of the silly thing without that script unless I plugged in and then removed headphones. Loved that machine though!