I hate to black pill you on cryogenics but brain cells are the first cells to die after a person kicks the bucket. We're talking about minutes here. You definitely wouldn't be able to get frozen less than an hour after death. Even if you hypothetically could, the odds of freezing someone's brain (even if you could somehow do it a second after death) actually preserving someone's consciousness is pretty low.
All scientific logic suggests that cyrogenics is nothing more than putting dead people into expensive coffins.