David can be counted out from what we seen in the novels and also in the alien movies and predator movies.
My explanation and vision:
In Prometheus we already see xenomorph like creatures worshipped by the engineers and from the murals its pretty clear the xenomorph already existed long time ago and that the black goo or Xenomroph virus as I see it is over 2000 years old.
In covenant David found designs and also xenomroph eggs that he started to reverse engineer and came up with his own kind of xenomorph after much testing and killing the colony of that planet, suing them as testing ground for his experiments. The species there was a creation of the engineers who they saw as a succesfull creation hence living in paradise, which David turned into hell.
The eggs we see in the movie are different compared to xeno eggs, they are shaped differently and colored differently if you check, rather than round eggs they are oval like.
The facehuggers move faster and impregnates their victims way faster, pretty much only a touch is enough apparently, xenomorphs needs 16-18 hours to impregnate the host.
The adult xenomorph is less biomechanic and more organic and thinner legs and arms and its pikes on its back is shaped differently and not to mention it behaves way different than the original xenomorphs and way dumber and much more aggressive, hell one tried to attack a robot arm, thinking its a living thing..... Also it crawls more on 4 legs than walking as big chap did.
Dont get me started on what we learn in the games and comics where its confirmed xenomorphs existed long before David tried to make them.
In predator 2 which is canon we have a xenomorph way before Coventant and also in the AVP, although some see it as a spinnoff but to me all alien/predator materials is canon, making it hard to fit everything together but its possible.
In the latest the predator which is canon as well we have a alien tail and confirmation predator 2 happened, more interesting is we also learn:
The predator species is made by the engineers as well, in the movie the yautja have exact same dna as humans and after all they do have the same build as a human, bipedal and human shaped. We humans have the same dna as the engineers and we know the engineers traveled all around the universe creating life, some successful species and some they marked for extinction.
My vision of the alien origin:
I agree with other fans and angry video game nerd that the derelight spaceship was on its way to some other planet and use the eggs as a weapon against some other creature we havent seen, this would expand the lore and its universe and recreate the mystery of them. Ridley scott himself said that the ships cargo, the eggs was its weapons.
To me it was the space jockeys we saw in the derelight space ship, a creature that is far older than the engineers who see them as their gods and try to look like them, it would explain the height and size differences and why their tech is so different, and why the space jockey have eyes and tounge and teeth visible and is clearly a fossil which Giger confirmed it to be.
The engineers used dna from the xenomorph to create their black goo/alien virus and also travels around the universe seeding planets, some planets where they see the creatures as worthy, will let them live in paradise like style with roman/egyptian looking architecture with a ship or docking station watching over them. Why we see the population of that colony on covenant waving and welcoming the juggernaut ship in the flashback.
In my vision the space jockeys died out a long time ago, they and their ships were biological beings, the ships alive and they grew like plants for their purpose, something which is alien to us and way different compared to the engineers who are too human for my taste. The space jockey in alien then did grow out in the chair as its role was to be the pilot.
The engineers are the space jockeys creation and looks up to them so much they design their ships and costumes to look like their creators. Trying to go in the same footsteps and create life on planets and xenomorph like creations, they see the xenomorph as another god, maybe as their devil?
They are far from excinct and as Ridley say will be back in the next movie, have to see what David has planned for them.
They however created us humans and the yautja, most likely other species as well.
End of my rant but this would expand the alien universe a ton and restore the mystery of it and where the xenomrophs comes from and fix problems with prometheus and covenant.
