I edit my previous post, after having renamed Serial to Serial 1.
When I talk about "firmware", thats not about my sketch, but about the USB emulated Serial port.
You won't have this specific class of problem from the ESP32 due to it not having native USB capabilities, but you will surely have plenty other problems that are just as tricky.
I allready moved to an ESP8266, and the things are running much better, and the existing litterature and experience are hugely higher!!!