With Heroku you are stuck with what they offer, and it quickly gets unreasonably expensive compared to AWS / GCP / Azure.
Digger is just as easy to use, but you don't overpay for resource and if you want something more custom, you can always do it directly in the underlying cloud account. Digger helps with that as well by generating Terraform modules that you can tweak for your needs.
Yes, Digger generates TF files and stores it in the dedicated "main" repository, separately for each environment. You can tweak these files directly, or override the defaults in the templates. So unlike black-box PaaS you retain full control of the infrastructure, Digger just makes this complexity optional.
Digger is just as easy to use, but you don't overpay for resource and if you want something more custom, you can always do it directly in the underlying cloud account. Digger helps with that as well by generating Terraform modules that you can tweak for your needs.