Fundamentally, Spock is the central character of Star Trek. His presence connects space, time, and reality. He has appeared before TOS and after DS9; he has appeared as an infant and an adult; he has appeared in an alternate timeline (Prime) and an alternate Universe (Mirror); he has appeared on screen with himself, he has died, he has been reborn, he has suffered the loss of his mind, he has suffered the loss of his brain. There is no axis of star Trek that can omit Spock.
Consider also that even putting aside the visual retcon of Star Trek: Discovery, Spock as a character has been played by a total of eight actors, two of which played Spock in his prime (Nimoy and Quinto). Spock is akin to Superman – a character who is instantly iconic and recognized, even though the face changes.There was no angst about Zachary Quinto’s portrayal on par with the angst currently suffusing Star Wars fandom over casting Alden Ehrenreich as Solo. We, the Trek collective, did not even have any real issue with Quinto-Spock receiving personal effects of Nimoy-Spock including the iconic cast photograph in which the visual discrepancy between all of the bridge crew was simply presented on screen without explanation or fuss. It simply was. It simply is.
Spock must appear in Season 2. We can quibble over warp nacelle shapes and surface veneer when it comes to the Enterprise, but even the critics of that design choice still had at least one heart palpitation at seeing the original NCC-1701 grace a television screen again for the first time in decades. Spock, however, is beyond debate.
Spock must appear in season 2.