Is this a sane idea to create a service with statefulset-like architecture outside of the kubernetes?

And is there some way to make this with GCE nowadays?

There would be app pairs, like backend app + database with an index for each pair. So VMs would have hostnames based on index + tier, for example, 3-app and 3-db.

Every instance can have metadata like index + tier + IP address, and which can be stored somewhere and should be deleted on pair removal.

And the whole thing can be managed (deployed & provisioned) with Terraform, Ansible, etc or by some Google Cloud service.

What was done: an old semi-automated stateful service that tastes like a meatball made of Nginx, Redis and Java and spaghetti of bash, python, and ruby. And it can't be ported to kubernetes, sigh.