This 5 series I'm currently using is a bit of a handful in loose snow tbh. and it's been severe here since Friday. However, I'm still managing to get about with some care. And that includes uphill starts etc.
Once or twice I've had to wrest control from the DSC - turn it off and let the rears spin - more accurately, churn gently - to get some uphill traction. This particular auto 'box is quite good because in manual mode you can over-ride everything, not just inhibit up-changes as is more commonly possible. So you can choose 3rd from a standstill and it will not go down the box or up it. You can't select 6 manually at all, but if you select 5 it'll still come down no lower than 3.
However, I still think that the Seat we had last January was superior in bad conditions. Small car, with a weighty lump of cast iron 1.9D dangling out ahead of the front (driven) wheels was impressively tractable in conditions that saw Freelanders and LRDs stuck because their drivers had no idea what to do.
In these conditions the brake/gear/steer separation method is essential.