Well, for one there is some canonical dissonance here. The description looks to be that of Other World, which... Well... The show literally depicted Grand Kai holding a depiction of the universe atop his index finger (can't show due to finicky Fandom image links, but it's literally featured on the Dragon Ball WIki's article for Multiverse), and it clearly shows Other World as the clouds above the material universe, yet it's all STILL contained within the universe. Also, Daizenshuu 4 (people normally view Daizenshuu as the most accurate DBZ guidebook of the bunch) shows the same depiction of the universe, with Other World marked as the clouds above the material universe (depicted as the bowl beneath Hell).
As for the room itself. Well, the room is clearly physical; all that thing would be getting would be Time Manipulation. Really, the Dragon Ball series had no flipping clue how time works! There's that room, which is more or less just a closet that Goku can physically interact with, so I highly doubt Goku's able to see anything 4D there. There's the Room of Space and Time aka the Hyperbolic Time Chamber, which is best assumed to be a pocket dimension considering Vegeta demolished the chamber enough to be given an ultimatum (basically, stop that shit or get banned from the chamber) and there had been no known instances of anyone who isn't from Universe 7 using the thing. That's not mentioning there are three known Hyperbolic Time Chambers: the one at Kami's lookout, the one owned by the Galactic Patrol, and the one Frieza found out of the blue. There's also the Time Rings, which Dragon Ball Super claimed were created each time a diversion in the timeline happens, and the Time Scrolls from Xenoverse, which are literally the same thing as the Time Rings but in scroll form. Oh, and the timelines? They don't affect one another; they just continue doing their own thing as if nothing happened. Weird, I know.
