Upon viewing the low-poly mesh I can tell I used the voxel remesher for the orc. The tri-count was about in that neighborhood of 2 million like yours.
I now remembered why I tried to use the instant remesher. I tried to instant remesh this:
I don’t think the results were favorable as I went and tried to manually retopo it myself. What happened was there was no symmetry so I had imported it back to blender, went to edit mode, and used the symmetry tool to make it even. As I write this, I also remember that I spent hours trying to remove the doubles along the crease where the center of the creature was.
Instant remesher was best for static objects that were not meant for animation. It still is useful in those cases as it can make a full quad mesh.
If you wish, I can walk you through the steps of the voxel remesher so you can get to the baking process. I do remember what I did for that as I baked the maps about thirty times trying to perfect the normal map anomalies.