By accident I found the freeware MMD to DAZ, v2 (2019) plugin. May require Microsoft Visual C++ 2015 Redistributable installed in Windows, which all but ancient dinosaur PCs should already have. Lets you import .PMD (older MMD) and .PMX (newer MMD) Miku Miku Dance figure files, apparently with the proper textures and bones, shaders, and toon outlines. You can also apparently drag and drop .PMX files onto the DAZ viewport.
Basic tutorial video: MMD Importer for DAZ Studio.
The other MMD option is said to be: Blender importer > FBX export (optionally also with dance motions) > Poser 11 import > save as .CR2 from which you can also take it to DAZ Studio. There may be other, perhaps better Blender importers by now, I haven’t made a huge search for them.