Obviously all depends on what you want to do. Here you have another more items but with connectors.
2.8''. I think it doesn't fit on the hole and place of the Devo 7 transmitter. The PCB probably is too much larger and will have problem with the space for the buttons. And the height of the screen is a little bigger than the hole in the transmitter.
2.4''. I think that this fits without problem. The hole is bigger than the screen.
2.2''. It also fits.
I can't imagine how to change the screen without soldering. ¿? If you change the main board by replacing with a generic main board, you will need to connect to it the potentiometers, switches and the new screen, etc.
When I talk about the hole you need see that the transmitter has a plastic frame with five screws, that you can remove by forcing a little to extract it and you get a bigger hole than the original for the original screen, and allows you to place there a touch screen.
I hope it will be usefull for you.