Why can't I get that grilled taste from my outdoor grill?
Based on your updated question, the major factor is that your fire simply is not hot enough to produce the charring and browning reactions you desire.

A steakhouse salamander (think of a broiler&mdash;grill in British parlance&mdash;which has flames on both the top and the bottom, to cook both sides at once) can be up to to 1000&deg;F and the elements are mere inches from the steak on both sides.

Gas grills have a maximum amount of heat they can produce.  The only thing you (may) be able to adjust is the distance to the flame.  The major cooking modality in a grill is infrared thermal radiation.   This decreases per the square of the distance, so the closer your food is to the burner, the faster it will cook (within reasonable limits).

Other than that, you may need new equipment if this is in fact the root cause of your issue.