Understood. One question, your cr touch is connected to your 4.2.7 board?
If yes, you don’t need the RPi as a secondary MCU.
My advise would be, start over. Follow the excellent Klipper documentation. Don’t copy stuff from somewhere in the www (particularly macros). If your Ender is pretty original (not regarding the extender), start with klipper/config/printer-creality-ender3-v2-2020.cfg at master · Klipper3d/klipper · GitHub. Just use stuff you understand. Do you know GitHub - th33xitus/kiauh: Klipper Installation And Update Helper? Have a look here About the Knowledge Base category / Table of Contents. If you have problems come back here and use the “search” button first. Almost everything was asked before 
I guess you come from Marlin, if yes you have to read a lot. If you don’t find the answer, ask here. People here are friendly and helpful.