Haven't used Blender Sensei, although it looks like a good idea, particularly if it works for you! It's a bit like using Linux Mint vs Arch vs Ubuntu vs RedHat vs SuSE vs Android... interfaces and needs vary, but everyone is using Linux (yes, Android is Linux). AFAIK, the .mtl file isn't used by Poser, but don't delete it, because the .obj file does refer to it.

Monterey/Mint21.x/Win10 - Blender3.x - PP11.3(cm) - Musescore3.6.2

Wir sind gewohnt, daß die Menschen verhöhnen was sie nicht verstehen
[it is clear that humans have contempt for that which they do not understand] 

Metaphor of Chooks