2006 Mazda 6 oil pump change

You need some punctuation in that huge sentence, otherwise it can be read at least three different ways. The oil pump is driven off the crankshaft snout. The front cover, timing chain, and crankshaft sprocket have to come off, but it's not necessary to remove the entire engine to do that.

What's more important is what are you going to do when the problem is still there? You didn't say what the symptoms is, so as a guess, the most common cause of a low dash gauge reading is a defective oil pressure sending unit. That can be verified by using a mechanical pressure gauge, or you can just replace the sensor. The second most common cause of low oil pressure is worn crankshaft or connecting rod bearings. That is not common at the mileage you listed unless the oil has not been changed regularly. When all other causes are eliminated, the oil pump is the last thing to suspect. They really don't fail that often. When they do, the most likely cause of low pressure is a broken pressure relief valve spring. Those can be replaced without removing the pump from the engine.