Digital Clock Delay app - unable to grant accessibility permission

I'm trying to set up the app named "Digital Clock Delay" https://freepoc.org/downloads/ to stop the clock appearing over the top of apps. The dev has a Youtube for setup which is easy to follow, however on first launching you need to grant it accessibility permissions. It takes you to the screen, but I don't get the list of all installed apps to choose from. The exact time code is 6:22 here https://youtu.be/0IymaRlW7qE?si=9d_MTMmkiR9a2JYl&t=382