lrwxrwxrwx 1 root root 10 Mar 19 18:43 klipper_host_mcu -> /dev/pts/1
You already have klipper_host_mcu but apparently no legacy System-V. Try
sudo systemctl restart klipper-mcu.service
and check the syslog for any errors. If there are none, then reboot and check if klipper_mcu is running.
drwx------ 3 root root 4096 Mar 19 18:17 systemd-private-c89fb609637b42ada7ea35b43c56532e-ModemManager.service-eIGKvi
ModemManager can interfere with Klipper. Disable it. See Other Single Board Computers (SBC) apart from Raspberry Pis
Most likely will not solve the issue unless you redo the complete Linux on your SBC