As a general thought, any idea if people have looked at something like (for example) using Proxmox on the physical hardware so the services can be put on VMs which can be migrated between hosts if there are problems?

Yeah I'm not criticizing it as a charity, just pointing out this definitely isn't "superior to most commercial services."

That being said, removing dependence on single hardware nodes isn't something you need a big team for. I've done failover at 1-person startups.