@Jamie Jonas I have some experience with TACOS (terraform automation and collaboration software). I've been using Env0 for 2 years on Azure in k8s centric environments. I've also used Atlantis, Terraform Cloud, and evaluated Spacelift.
Some of the things that I prioritize are:
1. Having the current state of any environment easily known. I came to an org where they were using Atlantis to run terraform applies in branches, so the state of any environment was an aggregate of open PRs.
2. A platform that enforces process. Editing a shared module and applying the change in one environment and forgetting to apply it to others is a ticket to configuration hell.
3. Having centralized places to find all Terraform runs. Browsing through a list of GitHub action results isn't a great user experience... especially when environments are split into different repos.
4. A platform that ENCOURAGES me to split up Terraform environments into bite size pieces. This allows me to separate concerns based on teams, issue permissions based on said teams, and allows me to run smaller changes more frequently with a limited blast radius.
5. A platform that allows me to define dependencies. For example, I have a core environment defined that defines vnets, etc. If I change it, I should automatically run plans on all the other terraform templates that depend on it and apply changes if needed.