Why didn't Lin Li just concentrate on one? In fact, that was a discovery he made during his research. The Divine-Smith-level mageweath was used to suppress the Ancient God of Light, so the laws involved in the mageweath were somewhat similar to the power of the Twin Serpents of Light and Darkness that suppressed the Divine Kingdom. It could be said that Lin Li's comprehension of the Divine-Smith-level mageweaths might give Lin Li a more profound and deeper understanding of the power of the Twin Serpents of Light and Darkness. That understanding might even give him more help in his research on mageweaths.
Although Lin Li didn't know how long it would take to study the Divine-Smith-level mageweath thoroughly, the gains he made during this study were also massive. The Divine-Smith-level mageweath was like a huge treasure that allowed him to reap a great amount of new knowledge with every bit of progress he made.