If still can't ssh the board via Ethernet, you should use UART console (/dev/ttyUSBx, /dev/ttyCH341USBx, etc.) to monitor what happened during booting.
If can't see the UART console in Linux (/dev/ttyUSB0 or /dev/ttyCH341USB0), according to https://github.com/juliagoda/CH341SER, you might need to do `sudo apt remove brltty`