The biggest advantage of 4WD is low range..... As a retired senior I grew up when 4WD was very rare yet we went everywhere with 2WD, does 4WD open more routes sure but it also ensures when you get stuck you are royally stuck...... And yeah, I love my Rubicon but I rarely go anywhere a driver with 2WD and skill and a locker could not follow.... but this is becoming a pissing contest so I'm done....
I use 4WD to go slower and tread lightly, 2WD just takes a bit more momentum to go the same places.
Flat out on topic with the OP...... He is building a fabulous overlander.