Kind of a shameless plug but it's hard not to with such a title.

Make sure to check out Spacelift[0]. It’s a CI/CD specialized in Infra as Code. Terraform/OpenTofu are first-class citizens and it brings advanced customizability with cross-statefile dependencies, OPA-policies (not just for access control, but e.g. customizing your gitops flow) and others.

The pricing is reasonable, too, and not per-resource. Generally based around concurrency.

Disclaimer: I work at Spacelift, but I do legitimately think it's a great product and recommend it.

[0]: https://spacelift.io