I agree to disagree, especially on that first count.
Why did the compositing come out like it did on disc then if so? I have only heard of a single report of that with a film print, over half a decade ago, not sure of the ultimate veracity.
The CGI on the Alien and the Neomorph in Alien Covenant varies wildly in quality. Compare it to Prometheus and it is no contest even the abandoned "unfinished Fifield" looks better.
As for blaming the craftsmen, every artist occasionally suffers under a medium or a subject they are not the best in, unreasonable requests, tight deadlines.