Ask HN: AWS cdk, serverless setup advice

I'm doing this part time work with another "senior/staff" developer who got tired of writing lots of code with nodejs and decided the way to go was doubling down on aws - and the various tools provided. His new stack is as follows

- dynamodb - nodejs lambda functions - s3 - cdk to setup infra, attach lambda's to various resources

nearly all our features rely on the following "common/reuseable" existing code. This is thoroughly tested because they are reused in multiple projects. -> we have a core set of infra/lambda code that does common things like -> authorization/authentication/accounts - using auth0 behind the scenes - for user management -> billing - using a stripe setup. we have ddb table, webhooks and various lambda to support billing based on accounts above -> managing uploads - presigned and direct multipart/form-data uploads and saving metadata in dd -> creating and tracking jobs - via sqs -> have api as a service module that helps us track useage for api's being sold to public

For a typical project, we spin up the above existing infra Add custom infrastructure to do things specific to the project This typically involves -> adding an api gateway and attaching lambda handlers -> and so on.

My question is Which of you do something similar How do you organize reuseable code - do you create your own custom constructs library? Do you have one giant gateway that custom apis get attached to or you create new gateways to do whatever.