Overall you're not doing much wrong, but simply choosing some unfortunate lines in the perspective grid. Also the ceiling would probably not be this low unless it is slanted? The rotated radiator looks great in this perspective and very believable!

A 1pt perspective drawing of my room from memory. Struggling with keeping the perspective consist with rotated items in particular and general spatial awareness.
Overall you're not doing much wrong, but simply choosing some unfortunate lines in the perspective grid. Also the ceiling would probably not be this low unless it is slanted? The rotated radiator looks great in this perspective and very believable!