I tried Pulumi 5 years ago because the idea looked cool and you could write code instead of HCL and apply things like loops etc.
However, the problem I found was that a Pulumi provider has two "sides", one is on the Pulumi side of the provider, which sets up resources to be created, but doesn't update them with the details of what's been created.
Example (may not be entirely accurate): You create a VPC, but then you want to use the default subnet as an input to another resource. You can't find out that subnet's information because when Pulumi runs, the "script" side doesn't get updated by the result of the VPC creation, so the information like the default subnet is "inside" the provider and not available to the user's script.
Terraform updates the resource that has been created with the information from the creation, so you can access the underlying AWS information in further resources.
However, the problem I found was that a Pulumi provider has two "sides", one is on the Pulumi side of the provider, which sets up resources to be created, but doesn't update them with the details of what's been created.
Example (may not be entirely accurate): You create a VPC, but then you want to use the default subnet as an input to another resource. You can't find out that subnet's information because when Pulumi runs, the "script" side doesn't get updated by the result of the VPC creation, so the information like the default subnet is "inside" the provider and not available to the user's script.
Terraform updates the resource that has been created with the information from the creation, so you can access the underlying AWS information in further resources.