With the steps and settings, you have provided, I am still unable to reproduce your issue. I can use the enter key on the button in the scroll box as soon as the game launches. I also looked at the project you provided, but it was an empty project. I have a couple more questions about your issue
- Does the issue occur at a specific time with your project (Only on launch, etc.)
- Is your project using a specific template? (First person, Third Person, etc.)