Front driven axle

[Doggy]

I have a new project in the making, but I dont really have much driving experience with AWD trucks on terrain as my first 8x8 project is still waiting on the shelf
As I tried driving 6x4 tamiya offroad, I find it hard to get traction if there is no load on the axle. I guess locking diff would make a big improvement in that area. But I would like to know how much of a difference a front driven axle makes in that concept? And do you need a front locking axle, or open diff is enough paired with only rear axles locked?