Let me turn this around. What do you think the hypothesis is, and how would you know if you've succeeded? Do not use the term "absolute zero" because you think that is a hypothesis, and not a definition.
No. The definition of Absolute Zero is zero kinetic energy of the particles of a substance. You've been complaining that this definition is somehow a hypothesis, or otherwise suspect because it has never been observed, which I've said, was irrelevant, we can calculate it. It's not hard. It's junior high physics. What's the kinetic energy of something that has stopped? It's zero.
Your position is absurd. It's equivalent of saying, that distance is an unproven hypothesis, (which literally doesn't make any sense, because that's not what the word means), or perhaps more charitably a suspicious concept because we've never measured anything with zero distance between two items, because the closest two particle can get is planck length.
I'm not trying to be mean, but what you've been saying is pure gibberish.
Let me turn this around. What do you think the hypothesis is, and how would you know if you've succeeded? Do not use the term "absolute zero" because you think that is a hypothesis, and not a definition.