Video to 3D

If you don't have 3D mesh, you can actually create one relatively easily using RealityCapture, a program (Windows only) that is able to estimate a texture 3D mesh from a set of images or (even better) a video.

Following instructions from this video will probably be sufficient info to actually create a 3D mesh. When you're done, import your created obj-file into Mesh-to-MetaHuman (more info here) and transform your mesh into a MetaHuman to be used in Unreal!