Yes lenovo may have made some changes because when device was given to us, it was locked to run any app other than some Educational Apps provided with device.I do not live in Delhi...
Also, just flash the stock rom using qfil only, that's more then enough, messing with device partitions is dangerous and there's also a slim chance that you might hard brick it...
But, I think that your school might have made some extremely low level changes to it, or might have paid Lenovo extra to remove direct boot to recovery mode...
For now, the temporary ways to enter recovery mode without adb are,
To reboot to recovery from magisk or from the power menu itsef...