Even if he does, how kind will it take him to add new functionality? For instance AWS both announced durable lambda functions and CFT support the same day

You could always use the plain vanilla resources that pulumi provides if there is no stelvio provided component for that.

I just checked, pulumi does have a good track record of keeping up with AWS. But using a non industry standard framework (Stevio) just doesn’t make any sense from a long term portable career perspective.

While I’m not a fanatic about which one I use out of the major ones. My last three projects were CDK/Typescript, Terraform and CloudFormation with my own collection of utility scripts I’ve used over 5 years to make it act more like TF. But the CFTs are standard.