If you just want to convert an OBZ to an OBJ, OBZ's are compressed OBJ's that can be opened & uncompressed in 7-Zip or WinZip. PMD's (Pozer Morph Delta's) which are rather common these days for morphs are a different story & will need to be exported as an OBJ, as you were planning.

It's a pity that the plugin for DAZ Studio 1.8 to 3.0 that read PMD's & allowed DAZ Studio to load them natively was abandoned.

EDIT: Corrected error