Uhmmm. No.
The only conclusion that you can draw from the LCD no longer working is that you changed the Firmware.
Sorry for coming in strongly but I think you need to go right back to the start.
First off, you need to exactly detail your hardware. This includes:
- What is the controller board that is in the Anycubic Kobra Neo. You may want to post a picture from your camera (making sure the MCU part number is legible). I’m saying this because Anycubic has used several different boards/processors over the years and we may have to track down information for your specific board.
- What is your host or “SBC” (this entry in your initial post wasn’t filled in)? Understanding where you got your OS and how you configured Klipper for it will be critical as well.
Once we have that, we’ll work through making sure your set up is correct.
@Sineos suggested that you read through Installing Klipper with KIAUH and that’s really good advice because it appears you’re trying to follow other people’s websites and Firmware builds and you’re not going to be successful following that approach. I was especially concerned with the link you passed with prebuilt firmware that is more than a year old.
Learning about Klipper, it’s architecture, how to build firmware and create configuration files is a bit of work but it’s not all that technical and it will serve you well over the course of time.
Let’s start with getting a complete understanding of your systems and what you’ve done and we’ll get things working for you.