5200s are great and the room is very important but there’s no getting over the physics when comparing 5200s to 7200s, in whatever room you like.
I heard one against the other (SE) demoed. 5200s were fantastic but when I heard the 7200s I nearly fell over. Huge difference in any room.
I’d scrabble for 7200s, then enquire with a friendly dealer if there are any .2 kits lying around from SE upgrades.
Standard 5200s aren’t much different from 5ks but a lot prettier.
As mentioned, putting quality source signals in can give remarkable results and those sources are getting cheaper and better all the time. Fun.