I have had and still do have high quality fh. When I see their big FAT heads squish against the side of the tank I smile. The genes have to be there period. If you dont take proper care of your fh the head wont grow as well as it should period.
Lots of bad and false info given out in this hybrid forum lately. Seems like you need to do some research. Like why and when a pure species male cichlid grows a nuchal hump. That is where our fh come from.
Maybe you want mfk hybrid section to be full of fantasy and misinformation but I dont.
So your stating that you know what is bred for a flowerhorn to be created? Please do tell because i'll tell you right now no one knows what was bred to achieve a flowerhorn.
You were stating that the genes didnt matter as much as how well you care for it here.
Its fat.
The genetics must be there but without proper care the head wont pop as big as it could. Like the op's situation. Feeding bad foods, keeping your fh with other fish, trying to breed it with another male flowerhorn etc will hinder the head growth. My water kok silk's head will drop if a female is bothering him or he isnt feeling well.
Keeping fh's with other fish grows the hump rather than make it smaller unless your fh is getting the submissive one. Water changes even make the hump smaller yet they return to their original size so you information about kok growth is very questionable.