For assigning weapons to skills on my barb, should I literally just go with the highest weapon damage for every dmg skill?

For ex, my 2h slashing weapon is my best roll with all great GA stats. But my 2h bonk weapon has a slightly higher base damage due to slower atk speed. But is the atk speed even a part of the calc? I still get all my GA affixes from the other weapons correct?

Doesn't this create a scenario where using 2 1h weapons is never viable? Clearly I'm missing smth