Installed Corn Head Grease in my new Luna Z1 Bafang Ultra Mag

It wouldn't. If it's a universal flaw why bother ? You're doomed.
If your gears are noisy 'it [might] reduces noise so much' temporarily.
Inherent poor design and bad gears meshing will not change.
A Creosote based lube might really help, but the noise is gears running on edges - singing 'help me, help me'.
Sharp surfaces cut right through grease. They want to be flat.
Low Powered motor's gears can take that. 100Nm and up not so much, but once they know riders work with it, avoid sudden high torque input, whatever.
The M620 now has a new steel gear-set - more teeth. That's how you make 'quieter'.
Not corn-combine grease.