I've never used Umbrel, but it looks like a normal OS... so it shouldn't be a problem to install it on any VPS with KVM via ISO image...?
https://github.com/getumbrel/umbrel/wiki/Install-umbrelOS-on-a-Linux-VM
Discussion
Okay, I think this might be what I'm looking for, thanks!
Any suggestions on a hosting service that isn't.. awful?
Choosing a VPS is a complex question, it depends on many factors, especially the desired location, price, connectivity, configuration, whether KYC is a problem, etc.
Vultr, DigitalOcean, Linode are global and easy, but more expensive.. More local hosting like european Hetzner or Netcup can be much cheaper, but often require KYC.
For non-KYC https://kycnot.me/?categories=hosting