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

I like this proxmox tutorial series:

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)