Character mesh low poly in object mode and high poly in sculpt

I used InstantMeshes to clean the high poly character 3D scan object, which had to much vertices to be practical. Now I want to adjust the muscle structure with sculpt mode, and I noticed that the

mesh - Modeling stylised fur - Blender Stack Exchange

mesh - Modeling stylised fur - Blender Stack Exchange

modeling - How do I smooth a low-poly mesh without shrinking its

mesh - Modeling stylised fur - Blender Stack Exchange

Mesh Replacement - Blender Stack Exchange

rendering - heightmap from textures and hight poly mesh to apply

modeling - How do I smooth a low-poly mesh without shrinking its

mesh - Modeling stylised fur - Blender Stack Exchange

rendering - heightmap from textures and hight poly mesh to apply

How to join segments of a low-poly character into one mesh without

modeling - How do I smooth a low-poly mesh without shrinking its

Superimposing multiple parts on a mesh - Blender Stack Exchange

How to join segments of a low-poly character into one mesh without

Superimposing multiple parts on a mesh - Blender Stack Exchange

My Mesh Distorts When Switching To Object Mode? - Blender Stack