there's nothing sound about the 'science of cryogenics' in fact there barely is such science at all if we're talking about the central sales pitch, which is actually bringing you back to life again in one form or another. Freezing you admittedly is straight-forward enough

The brain upload thing is a complete fantasy and science fiction, but even the traditional promise of somehow resurrecting you has never been proven with the exception of a 30-year-old tardigrade two years ago if I remember correctly.