Blynk device won't go online after adding LCD I2C codes in my sketch

[PeteKnight]

Your use of serial ports is totally messed-up.
If you’re using an Uno then you need to use a software serial port for you ESP device.
If you’re using a Mega then you need to be connecting your ESP device to Serial1 or Serial2, not Serial.

You should read this…

Understanding hardware and software serial ports

I’m still seeing frequent posts, mostly from new members of the forum, who are confused about how to add WiFi or Bluetooth connectivity to devices like the Arduino Uno, Nano or Mega, or from people who are trying to use serial communication with some other type of peripheral. I thought I’d try to put together some guidance on how to do this properly. First things first though – if you’re using a device such as an Uno, Nano or Mega that doesn’t have built-in internet connectivity then you shoul…

You also need to eliminate the blocking delays from your code. You should use a timeout timer instead.

Also the RTC methods have changed in Blynk IoT, you should read the documentation.

Pete.