EDIT:
BulletLukey has made an awesome world for this. You can join our realm (as long as it still runs) or download the world yourself.
In this world, it takes roughly 3,5 hours to get the achievement!You will need to play for 100 in-game days. Sleeping in game does not speed up the progress. You can track your progress, if you go to the ingame achievements tab. I would advise you to let your phone idle for a while. 100 in game days translates to 33 1/3 hour (1 ingame day is 20 minutes long).
You should be done in max 2-3 hours with the rest of the achievements if you have used achievement worlds. For the remainder of the +- 30 hours, I suggest to let your phone idle. I could only set my phone to go into sleeping mode after 5 minutes. If you're in the same boat as me, I suggest to download a macro such as tinytask, combining this with project my screen. Then plug your phone into your pc, record a macro of clicking on your screen. Now make sure your phone does not give any notifications for other stuff (as this might screw the macro up). Start a world on peaceful difficulty, and simply let it run over night or during the day when you're doing other stuff. An extra option is to turn both PC and phone brightness settings to the lowest setting to save energy. Besides, make sure your pc can not turn off due to the battery being empty (if you're using a laptop).