Can't help with 1, 2, or 3, but for #4 on my 2020 12" you could display the audio controls below CarPlay. That's how I usually had mine set up. The 22s with Uconnecct 5 can use the whole screen for CarPlay.Well for starters....
1. The mount is designed to clamp/crimp on the bottom of your phone, if you have a larger case, it doesn't work.
2. The charging cable ALWAYS get caught in the grove under where the phone drops in, so while futzing around to get the phone out of the "mount" the cable gets caught and invariably pulls out, shutting down car play... arghhh.
3. The phone mount is facing the rear of the truck (it's square) so using the phone at all is a pain in the ass since it's not facing the driver, so you have to pull it out... then see #2... cable gets pulled out.
4. That big beautiful screen we have is currently have is mostly (1/2) useless to iPhone users since we only get to use half the screen and end up with a stupid display beneath it that shows Sirius Weather or whatever... heck you can't even display the radio interface nor the on-board navigation screen, all of those take over the CarPlay screen. God forbid you hit a camera button and it would use that lower section... nope it replaces the CarPlay display. Love to take the software engineer who made this out behind the building on day...
5. Apple designed Carplay so that you are forced to use your phone to enter addresses on the move (when Siri voice screws it up) since they disable the onscreen keyboard when the truck is moving.
Really it is item number 2 and 3 that drive me the most crazy though I gotta admit #4 was the most disappointing about the nice huge useless 12" display unless you are using on-board Nav. If only the camera system could take advantage of the entire screen... nope. Grrrr.
Now that I have a movable mount I'm much happier. To each their own eh!
On #5, that's actually RAM, not Apple that did that. The phone gets a list of restrictions from the system it's plugged into. On my VW I used software (VCDS) to change the configuration and it gives me a keyboard now. Unfortunately even with AlfaOBD you can't make a similar change to the Uconnect system.