We don't even know what context Ock is being used in or if his sacrifice will even be insultingly undone as you claim. Saying that it'll automatically ruin him with barely any information (and what there is, is unverified rumors), context, and without seeing an ounce of footage first strikes me as very preconceived. This is why I have such a problem with people already calling the movie dead on arrival or that it will be another mess like SM3 and ASM 2. It seems like such a hyperbolic overreaction to me.
If No Way Home comes out and it blows, then you can deliver those criticisms, but it's way too early to start treating assumptions in a factual sense.
That being said, not liking the multiverse concept is definitely understandable as well as having reservations about the film.