Surface studio 1 and 2 both use the same fans, I have seen them available. below are some I found
https://www.amazon.com/Cooling-Microsoft-Surface-NS6CB01-NS6CB00/dp/B07TJR3C7N
https://www.mesioq.com/index.php?main\_page=product\_info&products\_id=382467
There is a video teardown of the surface studio by ifixit that shows how to remove and replace the fans, they are the same as the SS1. It shouldn't be a very difficult replacement.
https://www.ifixit.com/Teardown/Microsoft+Surface+Studio+Teardown/74448
I reccomend cleaning the fans and the cooling fins before deciding if you need to replace, mine had got a very thick covering of cotton wool like lint which when removed solved all my over-heating/noise issues. You have to remeber that essentially the SS!/2 have a laptop like cooling configuration and it is less forgiving than most desktop computers. I have a very dust free environment and I still get these very fine particulates cloggin up the cooling. I recommend a good dusting inside with a small soft brush every 3 months or so.