I am doing the exact same mod to my Nerve AM9 as we speak.
I have just tried to adjust the front mech (XT 3x) to account for the change in throw and height and it’s too big for the smaller system, I can’t get it low enough to the larger ring.
Just ordered an M786 front mech to suit the smaller chainring (XT M785 cranks 24/38) setup.
I wasn’t planning on fitting a chain device as I have the Shadow+ r/mech.
So, that’s my thoughts, I’m sure there’ll be others.