You can easily change your grab handle to a model with the keypad built in, but the hard part will be changing/adding the solenoid lock mechanism to your current door lock.
Trimarck is one of the big players in keypad doors and may be a company you want to contact. They may even know what you need inside the door.
Don & Mary
2019 Newmar Dutch Star 4018 (Freightliner)
2019 Ford Raptor