Just remembered a thing: one advantage of Blender over probably any other DCC is that Multires modifier (one that is used to hold subdivision sculpting data) can function after deformation modifiers, such as Armature, in the stack. Meaning that as long as model meant to stay in Blender, and computer can handle it, you can use your final detailed sculpt for animation. No normal or displacement maps are needed (save for micro details maybe), so no loss of details or hassle with baking errors.
Regular shapekeys already work from under Multires though. In most situations, they will suffice (provided you have enough polygons on base mesh level for areas you need to control)
Thinking about that, “multires shapekeys” would be trivial to hack in using Geometry Nodes. An algorithm to replicate a shape key is to subtract the base mesh vertex positions from the shapekey’s positions, scale resulting vector by shape value, then add to base position again. Since geonodes operate with final state of the mesh (after all modifiers), you’ll need several copies of the character with different sculpted expressions, but with synched skeletal animation. Slow, but I cannot imagine actual multires shapekeys being much faster.