ESP32 Code Fix for EEPROM Operations

I need a fix for my code.

I have existing ESP32 code reading 1k EEPROM first 5 bytes. I can read the EEPROM, store it, write it and it is functional. Printing the EEPROM values does not match known 4 digit.

sample:
for (int i = 0; i < BUFFER_SIZE; i++) { // Read data into buffer
buffer[i] = Wire.read();

What I need however, is to fix my code to also be able to have the read, convert it to a 4 digit decimal number on read, and then back to write the 1K EEPROM.

I tried below, but it did not work. I do not understand enough to know why and fix this. I posted below so you can get an idea of my attempt.

sample:
// combine bytes to form single integer value ?????
int result = (num1