As for Aksai combining the concepts of qi and Spirit essence together in a single weapon?
Aksai did not have the qualifications to think deeply about this matter.
He knew that the idea was tempting, but its execution was not going to be a walk in the park. Or more like, a walk in the farm.
Aksai had managed to obtain the 1st-order inheritances related to alchemy and Array Formations only recently because of the participation in the exchange meet.
It wouldn't be easy to get an inheritance related to artifact forging anytime soon. Not to mention, Aksai would also need to obtain various qi-based manuals and study them deeply before he could start experimenting with the fusion weapon.
These tasks weren't something Aksai could do on a snap of his fingers. However, he liked the idea so much that he decided to keep this objective on the back burner. He had finally made some acquaintances in the Dadangar World because of the exchange meet.
