KStars log extract:
[2021-09-25T11:48:32.416 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] Connecting to /dev/serial/by-id/usb-FTDI_FT232R_USB_UART_AL05YX86-if00-port0 @ 19200 "
[2021-09-25T11:48:32.416 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] Port FD 3 "
[2021-09-25T11:48:32.416 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] Connection successful, attempting handshake... "
[2021-09-25T11:48:33.422 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] CMD <3B 03 20 12 FE 33> "
[2021-09-25T11:48:36.539 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] CMD <3B 03 20 12 FE 33> "
[2021-09-25T11:48:39.657 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] CMD <3B 03 20 12 FE 33> "
[2021-09-25T11:48:42.778 EDT INFO ][           org.kde.kstars.indi] - PlaneWave EFA :  "[ERROR] Serial read error: Timeout error. "
[2021-09-25T11:48:42.779 EDT DEBG ][           org.kde.kstars.indi] - PlaneWave EFA : "[DEBUG] Handshake failed. "
[2021-09-25T11:48:42.781 EDT DEBG ][           org.kde.kstars.ekos] - "PlaneWave EFA"  is disconnected.
[2021-09-25T11:48:42.782 EDT INFO ][           org.kde.kstars.ekos] - "PlaneWave EFA failed to connect.\nPlease ensure the device is connected and powered on."

Relevant lsusb output:
Bus 001 Device 007: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC

Relevant dmesg output:
[ 4658.318868] ftdi_sio 1-1:1.0: device disconnected
[ 4681.309415] usb 1-3.1: new full-speed USB device number 7 using xhci_hcd
[ 4681.517596] usb 1-3.1: New USB device found, idVendor=0403, idProduct=6001, bcdDevice= 6.00
[ 4681.517614] usb 1-3.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 4681.517623] usb 1-3.1: Product: FT232R USB UART
[ 4681.517629] usb 1-3.1: Manufacturer: FTDI
[ 4681.517634] usb 1-3.1: SerialNumber: AL05YX86
[ 4681.527293] ftdi_sio 1-3.1:1.0: FTDI USB Serial Device converter detected
[ 4681.527389] usb 1-3.1: Detected FT232RL
[ 4681.528481] usb 1-3.1: FTDI USB Serial Device converter now attached to ttyUSB0