Stay as high as you want. The large epiphyllum indicates that the environment is suitable for vigorous growth. It is suggested that the main stem position should be kept at about 1 m, based on which, for example, the leek should be cut at 1 m and leveled. Branches and leaves will grow slowly soon (only this one needs post-management and maintenance by the owner).
Similar to this tree in the picture, the trunk parts can be tied together (not too tight), which will be convenient to manage later.