Look into proxmox, its a open source linux os that lets you deploy vms from a web browser.

I like this proxmox tutorial series: https://www.youtube.com/watch?v=LCjuiIswXGs

Type 1 hypervisor like proxmox are used everywhere in industry. It provides a nice GUI to do complex deployments involving clustering and Redundant Arrays of Disks

Here's some other ways to add redundancy to your setup: https://nullcount.com/how-to-add-redundancy-to-your-lightning-node/

I prefer to have many umbrel vms, one for money stuff and separate for media, socials, etc.

How much RAM? Depends on what all you want to run. I like to run max_mempool really high so I do 16GB per VM, but you could run comfortably on 8GB (VM not host memory)

Yes you should be able to do it pretty easy. Make sure you bridge the connection and RAM wise at least 8. Installed it in few old laptops in the past running Ubuntu and the VM manager within it

I have. Never had a problem, quite the opposite, as backup was very easy (I was using proxmox).
8GB ram

Are you running a non-linux OS?

Umbrel apps (including the umbrel app) are just dockerfiles, so it already runs in a "vm" but it does make assumptions about the operating system so I guess if you're not on a compatible OS you'd need to run a vm.