Really? When searching for keywords like OTA, pick most recent not most relevant, and compare results. But most references to OTA here will be using the ESP and C++
In fact I just posted >something about OTA< almost two weeks ago.
If however, you are looking for OTA methods for other devices, or languages like python, I suggest G 
GLE as OTA is not a Blynk specific issue. And >Blynk Python support< is in its Alpha infancy.
This is normal when you think about it… Serial monitor requires a USB connection, so when you set your IDE port for anything other than USB… well… “Serial monitor is not supported…” 