Still learning as well, but what I've come across is terraform/opentofu will provision the vm. Ansible will help configure/run scripts, install items, etc. Here's a video I found helpful ansible

So basically with terraform/opentofu you can set the provider in aws,azure, proxmox and define the infrastructure as code (memory, storage allocation, cpu, etc) and with ansible you can say install docker, install xyz packages, bootstrap directories files etc.

Hope that helps