In theory, if there was a top sect that wanted the Marquis of Longhua to join, as long as the terms are right, persuading him to betray Great Zhou could be viable.
Do not assume that the dukes and lords of Great Zhou are fiercely loyal to Great Zhou. Their loyalty stems from Great Zhou providing them with substantial benefits and influential backing.
But the problem is that the Marquis of Longhua can't fully accept some of the Western Region's ideological notions.
Shaolin Temple's martial artists focus on the cultivation of Buddhist law and spiritual cultivation. It's often said in Jianghu that Buddhists cultivate karma, and natural laws prevail.
The Western Region's Esoteric Sect originates from the same source as the Shaolin Temple, yet their cultivation methods are more extreme in comparison.
The Esoteric Sect of the Western Region focuses on body refinement, and doesn't seek karma enlightenment. They merely aspire to become Buddha through bodily transmutation.