To do that, I’m going to use a virtual UART ... board (the target board in the right part of the image). This second board is the one with the BLE and other peripherals. It doesn’t have a USB ...

Did you ever struggle with an ESP32 board of yours, wishing you had exposed that UART, or seriously lacking the JTAG port access? If so, you should seriously check out [0xjmux]’s ESP-PROG ...