How can I disable recovery mode?
OrangeFox Recovery allows option to lock Recovery with a Pattern or PIN 
It will prevent normal youtube users from reseting your phone
but their is a catch people with deep knowledge will flash
Fastboot ROM or Qfil ROM and make device useable again but all data will be lost  .

Best option is to use Phones in which bootloader unlock is not possible because of missing adb and fastboot devices like Honor

Regardless of what you do with some difficulty it is possible to fACTORY reset with proper tools by Government Agencies and then recover deleted data.