reference: https://forum.arduino.cc/t/startadvertising-is-not-a-member-of-bledevice/1086837/5
So change this part of your sketch:
#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>
#include <BLE2902.h>
to this:
#include <BLE2902.h>
#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEServer.h>