Yep if they add the sil creature who has a perfect body, unlike newborn and the black goo creatures that looks more like mutations and abnormal bodies, and having giger creatures and stuff mentioned, and even worse make them better than the normal xenomorph then we have jumped the franchise as the normal xenomorph is meant to be the perfect creature and deadliest in the universe, not lowest ranked and these new xenos are deadlier..... Just breaks it for me completely then.
The perfect organism is this:
nothing can be deadlier than this creature
Its perfectionism.
About the space jockeys looking biomechanical: In alien the space jockey room, the thing it is in and the floor around it is very metalic and normal, while the walls are covered in alien hive resin so I think the xenomorph design is just the hive resin that covers the interiour of the ship after the xenos escaped and bursted out of that space jockey.
but this was later in covenant sadly shown incorrect, but in alien its pretty clear it was the xenos doing, as we saw in the egg scene where the same hive resin covers the inside of the nostromo.