Yeah I'm 90% sure it all boils down to the fallout giger had with fox over alien 3 , I think fox and gigers estate basically just hate each other now.
Even if I take giger out of the situation , alien: covenant was just a bad film , the fact all those films boiled down to one renegade android creating the xeno was just ridiculous, there's a video on YouTube called the death of gigers alien , you should watch it , it basically gets at the heart of what is wrong with covenant.