a sample of manual setting the local time on ESP32 using arduino-IDE

esp32_rtc_manual_setting.ino

#include "lwip/apps/sntp.h"
struct tm gtmCurrentTime;

//#define DEBUGON

void fixDatetime(){

  gtmCurrentTime.tm_year = 2022 - 1900;
  gtmCurrentTime.tm_mon = 12 -1;
  gtmCurrentTime.tm_mday = 6;
  gtmCurrentTime.tm_hour = 17;
  gtmCurrentTime.tm_min = 30;
  gtmCurrentTime.tm_sec = 5;

}

uint32_t calcUnixEpochSecond(){
  uint32_t uiTmSec =
    gtmCurrentTime.tm_sec
    + gtmCurrentTime.tm_min * 60
    + gtmCurrentTime.tm_hour * 3600
    + countDateFrom1970Jan01() * 3600*24;
  return(uiTmSec);
}

uint32_t countDateFrom1970Jan01(){

  uint32_t uiTblMonthSumDate[] = {0,31,59,90,120,151,181,212,243,273,304,334,365};
  uint32_t uisum=0;
  uint32_t uiYear = gtmCurrentTime.tm_year -70;
  uint32_t uiLeap4 = uiYear>>2;//uiYear/4;
  uint32_t uiSub4 = uiYear&3;//uiYear - uiLeap4*4;
  uint32_t uiMonth = gtmCurrentTime.tm_mon;

  #ifdef DEBUGON
  Serial.print("uiYear= ");
  Serial.println(uiYear);
  Serial.print("uiLeap4= ");
  Serial.println(uiLeap4);
  Serial.print("uiSub4= ");
  Serial.println(uiSub4);
  #endif

  uisum += uiTblMonthSumDate[uiMonth];
  uisum += ( ((uiYear-2)&3)==0 )*(uiMonth>2);
  uisum += gtmCurrentTime.tm_mday-1;
  uisum += uiLeap4 * (365*4+1);
  uisum += 1 * (uiYear <= 30); // for 1972 to 2000
  uisum += uiSub4 * (365); 
  return(uisum);
}

void printTime(){
    Serial.print(" ");
    Serial.print(gtmCurrentTime.tm_year+1900);
    Serial.print(" / ");
    Serial.print(gtmCurrentTime.tm_mon+1);
    Serial.print("/");
    Serial.print(gtmCurrentTime.tm_mday);
    Serial.print(" _ ");
    Serial.print(gtmCurrentTime.tm_hour);
    Serial.print(":");
    Serial.print(gtmCurrentTime.tm_min);
    Serial.print(":");
    Serial.print(gtmCurrentTime.tm_sec);
    Serial.println(" ");
}
void setup() {
  Serial.begin(115200);
  // put your setup code here, to run once:
  Serial.println("initial time ");
  getLocalTime( &gtmCurrentTime);
  printTime();

  Serial.print("date to set: ");
  fixDatetime();
  printTime();
  Serial.print("config now...");
  sntp_set_system_time(calcUnixEpochSecond(),0);

  Serial.println("gettime :");
  getLocalTime( &gtmCurrentTime);
  printTime();

  Serial.println("wait 5sec");
  delay(5*1000);
  getLocalTime( &gtmCurrentTime);
  printTime();

}

void loop() {
  // put your main code here, to run repeatedly:
}