Amazing! This is the easiest C422 system I've seen yet. You may then change to OpenCore release, and add the OpenCanopy GUI if you like.
If you do post the boot log and SysReport folder I may still see if one could further optimise the EFI folder.
For USB you have to do the mapping yourself. Running "in production" with the port limit quirk is dangerous because it can cause buffer overflows. Follow here with CorpNewt' USBMap (read the introductory pages first)
If possible use a USB3
hub—this plugs to both USB2 and USB3 personalities, and does not need to be ejected. Else use both a USB2 and a USB3 device to find out everything. Test USB-C ports
in both orientations (this is important!). Make a sketch or a table of everything with the USB personalities (HS## for USB2, SS# for USB3) and the
hexadecimal port number 0x## for each (important!). Don't forget the SD reader!
If all ports come from the chipset, which is likely, you'll need to make choices to remain within the 15 ports limit. Tough choices if Dell went for the cheap solution and made
type 10 USB-C ports rather than type 9.
As for sound, you again have to do the mapping.
ALC3234 is ALC255, so layout 1 does not even exist. (I could have checked that beforehand.) Edit the config.plist, change boot argument "alcid=1" to "alcid=3", reboot and test all sound inputs and outputs. Repeat with each possible layout: 3, 11, 12, 13, 15, 17, 18, 20, 21, 27, 28, 29, 30, 31, 66, 71, 82, 86, 96, 99, 100. It's tedious but it doubles down as a good test that reboot is stable.
When you have tested all, make the best layout permanent, as boot-arg or in the DeviceProperties section.