I modeled a dragon and I am preparing it now to be printable :[![The problem][1]][1]


It selects nearly all the mesh, I do "merge by distance" is there a problem or what.
This is the method of how I applied the scale and size of the model in cm. This is the photo of that:[![enter image description here][2]][2]


This is the blender file before applying the scale :[blend. file][3]


  [1]: https://i.sstatic.net/W0ZjA.png
  [2]: https://i.sstatic.net/JRC78.png
  [3]: https://drive.google.com/file/d/1fFGGZkMOQqNqGTaRBdebSmhPBexfjiNL/view?usp=sharing