Making courses full screen on mobile devices

Hello, I am trying to make a Storyline 360 course full screen on a mobile device, but the button isn’t appearing in the player controls, even though the modern player supposedly has all the same features on desktop and mobile. I’m using the modern player, and I have confirmed that the full screen button is enabled in the player settings and that the button is present when I take the course on desktop. I’ve tried re-exporting and uploading to my LMS as well as uploading the course as Team slides and creating a new Storyline file. I’ve tested the course on my iPhone 13 Pro on both Chrome and Safari and I can’t see the full screen button on either. I also know that turning the phone landscape makes the course bigger, but it’s not really full screen.