Subjectively, the AWS provider will at least validate that fields have valid values during the plan step. The Google provider doesn't seem to validate actual values until apply, and then you get a failure
It (well, the provider) doesn’t validate fields until apply. That’s just so… sad. How is that acceptable? It’s like a car without a steering wheel, and people just go along with it.
It gets hairier when you delve into the details. The provider is typically an official provider that wraps some company's API, so that company ought to have a good set of validations, since it's their own API, right? Wrong. The team that writes the Terraform provider is typically different from the team that creates API methods, and the API methods themselves don't typically expose "dry-run" style functionality, so there's little for the team writing the Terraform provider to check. Meanwhile, the business doesn't care - the Terraform provider checkbox is already checked and validations/dry-running isn't a feature that affects revenue.