Radek

if you have WiFi connected to TFT and TFT communicates with SKR, WIFi should also communicate. Must have WiFi to TFT serial port enabled (you have it) The same communication...

I have no experience with the KAD configuration, I cannot judge. But I'm quite confusing for me. Send a photo of the connection

The web interface of the wifi adapter doesn't suit me very well. I connected the printer's WIFI adapter as a virtual serial port and I connect to the printer via...

Will this help? https://github.com/bigtreetech/BTT-Expansion-module ESP-07S  ESP-12E/s 

Read this https://github.com/bigtreetech/BIGTREETECH-TouchScreenFirmware/issues/1324

Use a shielded cable for serial communication 

The UTP cable is not shielded. The FTP cable is shielded, but it is unnecessarily strong. I used a USB cable from an old mouse. 

A heated bed powered by PWM is a huge source of interference. If the display is within range of electromagnetic waves, it may be affected (disturbed).

You can still turn off the PWM bed control in Marlin

This is already ghost hunting. Try to separate the 5V power supply from the printer to the display. Use a separate 5V power supply (such as a USB phone charger.)...