A simple look into the log would probably have brought you further:
mcu 'mcu': Unable to open serial port: [Errno 2] could not open port /dev/ttyS4, UART: 16550A, Port: 0xf0e0: [Errno 2] No such file or directory: '/dev/ttyS4, UART: 16550A, Port: 0xf0e0'
Where did you find the information that this construct is a valid connection string?
Follow Issues flashing the printer board
For a printer that has apparently never worked before your entire config seems pretty complex and overloaded. Maybe it would be better to start completely over with Installing Klipper with KIAUH and get the basics working.