Unfortunately, there is no way to rotate the device on the Presentation tab. You need to go back to the Design file tab, open the Prototype panel and set the desired device orientation.
“Note: It’s not possible to switch between orientations within a prototype. This is something to bear in mind if you have frames in your prototype across both orientations.”
Is it a joke?
I can’t even manually assign preview orientation for different frames?!
My prototype is a mix of landscape and portrait views, so you are suggesting I have to go in and change preview orientation every time I try to preview a frame of a different orientation?
Very poor UX design by Figma team
Rest assured, device orientation will work inside the mobile application. Not perfect, but it does a good job.