And what assurances are there that you will be around for five years? Or that you will support new services features when they come out?

And I always “disable rollbacks” this has been a feature in CloudFormation, CDK and SAM for years.

Running lambdas locally with SAM has been a feature for at least 5 or six years as with the CDK. But these days you really should be packaging lambdas as Docker containers - those are really easy to test locally without any special infrastructure