What to do when a seemingly final action is not the final action

I'm trying to solve this simple workflow. For context:

• A user accesses a page to read a document
• The user can suggest changes on that document, or not
• In either case, the user has to click a button that says "Submit review..."
• After this, they see a modal confirmation explaining what is going to happen.

In all my tests, users were able to understand that they have to click on this button because there is instructional text that says "Once you have finished please click Submit review... for confirmation."

They all understood it, but, I still feel is not really clear that this is not the final action, since they will have a confirmation modal. In fact, all of them said that it was good to have a confirmation modal before the final action, but none of them were expecting it.

How might I make this simpler?