Pulumi was a one trick pony that never figured out a way to differentiate themselves before HashiCorp caved and delivered a Terraform CDK (Terraform for the longest time was extremely hard to use programmatically, you basically had to wrap the binary, you couldn't import a lot of the underlying Go code directly) (aside: HashiCorp still does this with Consul and friends, very annoying and has clear intentions on why).
I would master Terraform modules with HCL before reaching for a CDK (or Pulumi). You may find you don't need anything more, or you'll figure out why you need those things instead. Plan your automation journey with the end user in mind but not an immediate goal, service your own needs first and eventually build out tooling _designed for them_.
Really? Why? Trying something new before becoming a "master" in something similar seems like a totally reasonable concept to me. I work on Pulumi, and even I don't actively discourage people from trying its alternatives. Use what makes you happy, I say.
I would master Terraform modules with HCL before reaching for a CDK (or Pulumi). You may find you don't need anything more, or you'll figure out why you need those things instead. Plan your automation journey with the end user in mind but not an immediate goal, service your own needs first and eventually build out tooling _designed for them_.