I think the DiDism or is or is not 5e comes down to alterations of the core system.
You go to 4 scores instead of 6. Not D&D.
Take out advantage and disadvantage? Not 5E.
Take out skills and replace it with nothing that office that same mechanical support? Not 5e.
Removing Cantrips and rituals from casters? Not 5e.
There's a difference between addition on top of the system and addition while replacing the system.
Once you start messing with the guts it's not 5E anymore and/or not D&D anymore.
You go to 4 scores instead of 6. Not D&D.
Take out advantage and disadvantage? Not 5E.
Take out skills and replace it with nothing that office that same mechanical support? Not 5e.
Removing Cantrips and rituals from casters? Not 5e.
There's a difference between addition on top of the system and addition while replacing the system.
Once you start messing with the guts it's not 5E anymore and/or not D&D anymore.