Oh brother. Not this again. The size of the Enterprise has NEVER been stated on screen, ergo there is no canon to violate. The earliest references to its size (The Making of Star Trek) are also conflicting -- it's said to be 947' long, but at the same time the shuttle bay is described as being big enough to house multiple jet liners. Huh?
The Enterprise from In A Mirror Darkly was scaled as 400-450m, which matches what we see in Discovery.
It's easy enough to work out from the visuals, since we know the diameter of the bridge and the size of shuttles - it's about a thousand feet long give or take.