Using Blender 2.83
Here’s the versions that work on Blender 2.83.
Import / Export works perfectly, but Blender had crashed very frequently while playback with physics, so you should use them only for model editing.
MMD Tools 2.5.1 https://github.com/UuuNyaa/blender_mmd_tools/releases/tag/v2.5.1
UuuNyaa Tools 1.6.0 https://github.com/UuuNyaa/blender_mmd_uuunyaa_tools/releases/tag/v1.6.0
credit: Ellen Joe (Zenless Zone Zero)