Too Long; Didn't Read
This article leaves out some boilerplate code, like creating the stacks. I've spent the last few weeks researching how to connect event busses in two different AWS accounts using the CDK. Fortunately, the final solution isn't that complicated. The CDK creates both a bus and an IAM Role that will allow the bus to send events to the receiving bus. Without any fancy setup, you'll need to deploy stacks at a time using the proper time for each profile for each account.