The engine is going to warm up whether you do it at idle, or with a moderate load on it

The first has the longest duration warm up cycle, so the most engine wear.

The second has a shorter duration warm up cycle, so less wear.

Drive away, moderately, as soon as the windscreen is defogged, or whatever else takes a few moments. Don't rev it up high until the oil is to temperature, which takes longer than the coolant.

Or don't, and just accept more rapid wear.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue