On the use of Strength, and other natural attributes

The lighter guys need to use strength in a far more intelligent and discriminatory fashion. They cannot just use it when they want to but must work the angles to make what they have more efficient

The bigger guy can get away with more, knowing that his strength can protect certain areas with less effort. And if worse comes to worse they can always access that strength difference to gain the advantage

Is this wrong? No, not at all.
If your natural strength can be used in an advantageous way, then, by all means, use it. I definitely do when and if I can. Just as if you were more explosive or flexible, then you would use those attributes

The trouble comes when you are countered by someone who is equal in those attributes or when they can use one or more of another attribute to stuff your game

King of everything then becomes intelligence and efficiency, knowing which skill set and approach to deal with what your opponent presents you with. In other words Strategy

So what will make you more intelligent and efficient? The ability to move.

The ability to follow/hunt/chase/force/maneuver your opponent into submission positions
The ability to
avoid and counter being followed/hunted/chased/forced/
maneuvered into submission positions

So focus on your movement, and use your attributes as an auxiliary supplement instead of the opposite way round.