Our software development lifecycle has 5 environments. We also wish to spin up dedicated, short lived environments for individual Developers. As a result, we'd like to have two M40s, an M10 and two M5s for our SDLC and the ability to spin up M0s for the devs.

The way you've implemented the terraform mongodbadvancedcluster resource makes it exceptionally difficult to use the same code across all environments. This isn't in keeping with best practice for terraform implementations, which is to use the same code and only change the variables. Might I suggest you add providertype and allow values such as "DEDICATED" and "TENANT" and change providername to be used for both tenant and dedicated. This would allow you to get rid of backingprovidername.

Also, make variable declaration uniform across all provider_type installations.