This is generally more for deployed, mission critical, WiFi devices... not tethered USB devices.
I know, that's what I use all the time as well and attempting to use those connection management commands tends to just confuse the poor USB interface and destabilize my connection.
The USB link is more for benchtop testing, and does behave differently (from what I can tell) from standard Ethernet/WiFi and even GSM.
Also, all my Arduinos restart whenever reconnecting the USB script, I think it has to do with the Arduino firmware for the USB programming.
Not sure what you mean here... In my view, Blynk is a Server based, library & GUI addition to "normal" MCU coding methods, with it's own specific purpose and required process of coding that enhance IOT type processes. But if your project works fine without it... then why are you trying to use it?