Oversimplifying it, Ansible playbooks are nothing more than some commands that should be run on a remote machine via ssh. Ansible knows or has modules for a variety of different package managers (apt, yum, etc) and automagically knows how to handle services or various config files.

It can get complex, but I think just the startup phase, until you have an inventory of remote machines, the ssh keys are in place, etc. I second the Jeff Geerling recommendation, his stuff is solid, both ready to use playbooks, and tutorials.

I would suggest to also look into cloudinit. Makes setting up VMs on proxmox easier, faster, more consistent, with users, networking, ssh keys, etc ready to use (by you or by Ansible).