That paper is using uniform heat sim dies as does all experimental testing, hence term uniform heat flux. Modern cpus, like 9900k, have hot spots where heat is concentrated on small sections of the die which decrease the effective surface area dramatically. Which is why you can have a 15-25C gradient just through the die. Copper water blocks or copper IHS spread heat at rapid 400 w/mk to a more uniform temp (intel claimed in past white papers to within 1-2C spread vs up to 10X higher temp spread vs bare die hot spots).
Even if there is a multi-jet design (like the one IBM abandoned 15+ yrs ago even though they milled microchannels in die to deal with hot spots) that can cool a uniform heated sim chip 10-15% better than a 15 year old design waterblock (and maybe as well as a modern waterblock), that would not suffice. It would have to perform multiple times better than a cold plate, because without spreading the heat via copper it will have multiple times lower surface area which will will proportionally lower its effectiveness.
Ill believe it when I see it tested independently on an actual intel cpu dissipating 200+W at load. So far its been 15 years, havent seen it yet.