Personally, I don't get the movement to Stainless Steel away from brass and plated brass. In comparison brass wins every time: Brass threads are smootherr than stainless steel and brass holds the heat whereas stainless steel get cold quickly. I suppose the one paramenter which I can understand is that stainless steel lasts longer than plated brass. However I am currently using Gillette Tech razors which are plated brass and which were made in the 1950s and still going strong. Zinc alloy otherwise known as Zamak or Zamac is simply the modern equivalent of brass,
The razor in question, Yaqi Avanti, is listed as 316 and nor 316L and is not stated to be CNC machined. That probably means it is cast and then polished. It is therefore a cheap Chinese Clone which is sold at a premium!
Steel actually holds heat better than brass - it has a significantly lower heat conductivity (exact number varies depending on alloy specifics). That, however, also means that it takes it longer to heat up, so while brass might take a minute to warm up, you'd need to have steel exposed to the same amount of heat for a longer time.
If you're comparing how smooth threading is, from what manufacturers were the razors the threads of which you were comparing?
Were you comparing razors from the same manufacturer, made using the same process?
I'm rather unsure whether there was an actual move away from plated brass to steel, as, if I remember things right, the transition was mostly brass → brass+aluminium → zamak (when looking at just Gillette Tech, for example).
I think that, for a while, Fatip was the only manufacturer who would keep up production of brass razors while pretty much everyone else went to zamak (with the occasional brass thread).
Then a few smaller manufacturers started producing steel razors (I think Feather and Above the Tie might've been among the first, but I might well be wrong there).
You're also glossing over the fact that plating varies in quality, and there are many vintage Gillettes with fairly significant amounts of plating loss.
I've had Fatips with plating loss (mostly the Special Editition, which is rather infamous for it), too, and while I haven't babied them, I haven't treated them harshly either.
I haven't held the Avanti in my hands, but it seems unlikely to have been cast - casting steel on the cheap is pretty challenging without bubbles, and even MIM has some telltale signs (I think it's why pretty much all MIM razors have a satin or matte finish).
and would consider one made of premium metal