Luckily, you only need to get internal track approval the first time. After that, you can deploy changes to your own team with fast, automated review.
But, as my conversation with support showed, even after getting internal track approval, you'll need to wait another three days when you want to go live for production approval. ("It should be slightly quicker, but again we recommend three days just to be safe")
There’s still a review process for the “internal” track even for an established app, and sometimes it gets held up. I think “internal” is a misnomer, it doesn’t seem to be handled any differently from a closed alpha channel.
But, as my conversation with support showed, even after getting internal track approval, you'll need to wait another three days when you want to go live for production approval. ("It should be slightly quicker, but again we recommend three days just to be safe")