Unlike Thomson, I am not with Laminar Research; just a flight simmer.
What do you want to finally achieve? Upgrade from XP10 to XP11? X-Plane 11 is a totally different package (like a Rolls Royce to an Audi) whereby you will have to purchase XP11.
Why do you want to go for a Steam version? It is a third party hybrid that is taking a commercial advantage of the development work carried out by Laminar Research. Steam versions are always days behind any officially released versions of the original versions of X-Plane.
Support the developer and not the hybrid.