Great, then we both have physics PhDs, and you'll know that none of that equipment has, or easily could be, sufficiently miniaturized, which is the topic of discussion ("extremely small cryocooler"). You can't put nested closed dewers of liquid nitrogen and helium on a O(1 mm^2) microchip, and the reason is exactly what I said: it will warm up too fast.
The topic is cooling small objects so that personal electronics (e.g., your phone) can compete with datacenters. Cold at scale (i.e., in datacenters) is comparatively easy.
