hi could you please document your source of these building heights? It's a bit hard to claim you're "fixing" them without backing up how you came to these results?

Also for example https://www.openstreetmap.org/way/466884767/history I set both ele and height, so that you can obtain the elevation of the top of the building, which could make 3D rendering more accurate as you're less dependent on the DEM, adjusting just the height without changing the ele would move the top of the building elevation.