I like what you've done with the haed and dorsal spines, and shifting to a quad-limbed model neatly avoids having to work out how to make double shoulders look good.

My immediate impression of the wings was that the struts are too heavy / there is too little wing area for something that size {Yes, I realize the inherent futility of debating the physics of a fantasy beast, but it just doesn't look plausible to me…}

Adding a bit of three dimensionality to the claws (particularly those on the legs) would also be nice…

Cheers on figuring out blockbench as well 🥂