Perhaps it was due to different circles, information hard to come by in Pengcheng was easily accessible in Kyoto, or perhaps Gavin felt that Dong Tianyu's cultivation level had reached the Path Entry Realm, so he didn't hide how to use artifacts to break through.
"To use an artifact to break through your cultivation level, first and foremost, you must not merge with the artifact before you have fully mastered the Energy Refining Realm. That is a prerequisite."
Dong Tianyu understood this condition, since after merging with an artifact, even the energy cultivated would be absorbed by the artifact, accelerating one's control over it and enhancing the artifact's powers.