finally got it right, I sourced an ESP_Prog board and a 'no name' CJMCU FT2232HL (purple board from aliexpress).
With ESP_Prog I've had such strange cases that something that worked yesterday doesn't work today and no one knows why. And then it works again. But with the purple board - no problems, and all pins of the FTDI 2232 chip available, which means you could use the second UART to communicate with ESP32. The only problem with this board is the poorly attached usb socket, which will probably break with a few careless moves.
Perhaps the ESP - prog also works ok and I did something wrong - the end result is that I have two working jtag interfaces now.
