So, by my reading, the printer works, the cable works, and it works with OctoPrint. OctoPrint sees a serial port, but it gets no reply from it. I would say that by process of elimination, that there is something wrong with the configuration in the VM to pass through the USB device, because everything else (sounds like) it has been ruled out.
2022-06-04 19:16:00,503 - Trying port /dev/ttyUSB0, baudrate 115200
2022-06-04 19:16:00,504 - Connecting to port /dev/ttyUSB0, baudrate 115200
2022-06-04 19:16:00,566 - Handshake attempt #1 with timeout 5.0s
2022-06-04 19:16:00,567 - Connected to: Serial<id=0x7f187019b880, open=True>(port='/dev/ttyUSB0', baudrate=115200, bytesize=8, parity='N', stopbits=1, timeout=5.0, xonxoff=False, rtscts=False, dsrdtr=False), starting monitor
2022-06-04 19:16:00,569 - Send: N0 M110 N0*125
2022-06-04 19:16:05,577 - Handshake attempt #2 with timeout 5.0s
2022-06-04 19:16:05,607 - Send: N0 M110 N0*125
2022-06-04 19:16:10,594 - Handshake attempt #3 with timeout 5.0s
2022-06-04 19:16:10,598 - Send: N0 M110 N0*125
2022-06-04 19:16:15,604 - Trying port /dev/ttyUSB0, baudrate 250000
2022-06-04 19:16:15,608 - Handshake attempt #1 with timeout 5.0s
2022-06-04 19:16:15,610 - Send: N0 M110 N0*125
2022-06-04 19:16:20,617 - Handshake attempt #2 with timeout 5.0s
2022-06-04 19:16:20,621 - Send: N0 M110 N0*125
2022-06-04 19:16:25,629 - Handshake attempt #3 with timeout 5.0s
2022-06-04 19:16:25,633 - Send: N0 M110 N0*125
Also, it is trying to autodetect with 66 different candidates - I would suggest manually selecting the serial port, you have /dev/ttyS[0-31]
also in the mix which will just slow you down.
I have no knowledge of Promox and the configuration there, but I would suggest either checking that, or maybe posting whatever configuration is used there so that if there is someone who does know how it works they may be able to see what's wrong.