Cancellation is not the same as "erasure from canon." Lot of popular shows get cancelled all the time - Lower Decks got cancelled as well. Despite the narrative, Discovery was popular. It was a success.
Discovery is still canon. The premise of this thread is a conspiracy theory which is not factual. Star Trek Discovery is still a part of the Star Trek franchise. You can still purchase official Discovery memorabilia. You can still stream it. It has an official Blu-ray release.