Ok, both laser and vinyl cutter seem to live in harmony. When I turned on the laser, Windows installed a FT245R USB FIFO driver. When on “auto” port, Lightburn showed the laser disconnected, started working when I manually switched it to the new COM4 entry.
So drivers look like this:
COM3 Vinyl cutter: FT232R USB UART, FTDI 2.12.28.0 8/16/2017, MS Win…Publisher
COM4 Boss Laser LS-2436: FT245R USB FIFO, FTDI 2.12.28.0 8/16/2017, MS Win…Publisher