There are approximations in figuring entropy and thermal statistics that may be wrong in very nearly immeasurable ways. The one that used to stick in my head was the calculation of the probability of all the gas in a volume showing up briefly in one-half the volume. Without doing math I figured it is actually much less than the classic calculated result, because the classic result assumes zero correlation between where any two molecules are, and once any kind of significant density difference exists between the two sides of the volume this will break.

But entropy is still real in the sense that it is "out there." An entire civilization is powered (and cooled) by thermodynamic engines, engines which quite predictable provide useful functionalities in ways predictable in detail from calculations of entropy.

A glass of hot water burns your skin even if you know the water and the skin's precise characterization in parameter space before they come in contact. Fast moving (relative to the skin) molecules of water break the bonds of some bits of skin they come in contact with. On the micro scale it may look like a scene from the matrix with a lot of slow moving machine gun bullets. The details of the destruction may be quite beautiful and "feel" cold, but essentially thanks to the central limit theorem, a whole lot of what happens will be predictable in a quite useful, and quite unavoidable way without having to appeal to the detail.

I think the only sense in which you can extract energy from water with a specially built machine that is custom designed for the current parameter space of the water, it is the machine which is at 0 or at least low temperature. And so the fact that useful energy can be extracted from the interaction of finite temperature water and a cold machine is totally consistent with entropy being real, thermal differences can power machines. And they do, witness the cars, trucks, airplanes and electric grid that are essential for our economy. The good news is you can get all the energy you need without knowing the detailed parameter space of the hot water, which is helpful because you then don't have to redesign your cold machine every few microseconds as you bring in new hot water to it from which to extract the next bit of energy.

Entropy is as real as energy whether it feels that way or not, and that is why machines work even when left unattended by consciousnesses to perceive their entropy and its flows.