@NickAVD
Even if you cannot move it directly to the window, I think just being able to look out there even if from a distance adds something
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Have you tried how your dragon reacts when the curtain is open?
(I always leave the curtains behind and right to the terrarium open during day, and just close them during night which I do mostly because of light pollution from outside - street lights, harbor.)
Does it warm up during summer through the glass? Here it does. (But our summer temps might be well above yours, plus we have for sure more direct sun i.e. without any clouds.)