Cannot create an ECS Fargate Internal Service

To create the association between fargate tasks and target group registrations, the target group must be created during service creation. But you can't create an INTERNAL service using an internal load balancer this way, because it defaults to INTERNET FACING. So the load balancer has to be created first, then I have to delete the listener and temp target group and choose the internal load balancer. But there is no option to choose a port when creating a target group, so non-standard ports don't work.

This is a terrible design.