It will only make the muscle lines more obvious

Stronger

Because fitness will increase the diameter of muscle fibers.

And lose fat.

Of course it won't increase the waistline.

The best way to increase waistline is to gain muscle fat.

But it is not recommended that you increase fat in order to increase your waistline.

My suggestion is

Comprehensive development

Whole body fitness

Remember to develop in an all-round way.

Make a short-term plan first

Then make a medium-term or long-term plan according to the effect.