Presuming our 2020 GT5 34H5 is pretty much the same:
The mattress is about 8" thick and the top of the mattress is about 25" off the floor. We both prefer a firm mattress and this one feels really good to both of us.
If you have the same Jensen XRV10 10.1" display used in 2020's, no, it does not have Apple CarPlay or Android Auto.
However, it does have Bluetooth and we stream SiriusXM from a phone to the Jensen. One thing we've noted on ours is that the phone does not automatically pair up sometimes. To fix it, we just turn Bluetooth off on the Jensen touchscreen and immediately turn it back on and then it reconnects fine.
There is an MHL (mobile HDMI) cable on ours stuffed behind the radio and MHL is selectable from the Jensen touchscreen. I think the 2021 brought that cable to a jack on the front panel per LaLaLisa but they have a GT7, not a GT5. In any event, if there is an adapter cable for your iPhone to MHL and you have the Jensen XRV10 you could try that.
This is the manual for ours: https://www.asaelectronics.com/downl...v10_stereo.pdf
We have a tan interior so I have no idea on the color. We did see it at an RV show, I think, and I liked the gray cockpit a lot better than the tan one we have. I think the floor linoleum also was a bit more gray and looked good to me.