Earlier quoted context omitted.
Two vms on the same machine doesn't help when the machine fails. Also, I sure hope your loadbalancers don't suck. I've worked with some that had worse uptime than my servers, and worse capacity too. Went back to putting the two host addresses in DNS, which is mostly fine, but means a lot of waiting when you want to take a host out of rotation for disruptive maintenance.
I do this on AWS so the load balancer is managed for me. Never had issues. Two randomly provisioned vms are unlikely to be on the same bare metal.
You do have some control (quite typically?): https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placemen..., https://docs.hetzner.com/cloud/placement-groups/overview.