If you want comfort, you want a compliant seatpost with a lot of length showing and decent tyres. I've a Maxlight XC. I started with a heavy and stiff RaceFace prodigy post since it was the cheapest thing CRC had in the size when I bought the frame. Had a few rides and was not impressed, was thinking of binning the whole hardtail idea and going back to the FS. Bought an Easton EA50 post from here basically because it was cheap and the colour and logos matched the bike not really expecting a difference in ride, but it transformed the ride, comfy as a comfy thing in comparison. Whether it's layback or not is not relevant.

It depends on loads of things- tyres, the particular frame, the rider, the seat and seatpost, quite a lot of the other components in fact. My Scandal was exactly as comfortable over distance as my Soul, my old Kraken was stiffer but still perfectly comfy. Think a lot of cock is talked on this subject by the "steel is real" crowd 😉

my steel old school sunn is way more comfortable than the cheaper stiff alloy bikes i've used. Depends on the actual frame i would have thought and the construction rather than just the material.