no it's not included in the box
you'll need to buy it yourself. when i was looking at getting a 13900K i saw people recommend using one of these plates. i'm not dealing with that shit. either design your products properly or include that in the box.
as for PSU. it doesn't matter where it is. it used to be common for PSU's to be mounted in the top. as long as your cables are long enough (they probably are) then you'll be fine. you could argue about cooling in that the heat from your CPU/GPU will go up into the PSU but it's probably insignificant. i suppose you could turn the PSU around so it's drawing in cool air from the top (if there is holes in the case for it). if the case has a shroud around the PSU then it won't make any difference at all.
you aren't building it yourself? you should probably try do it yourself. we'll always be here to help you