Exporting your character from Blender to a Game Engine is hard.
Especially if you don't understand the underlying tech (and frankly, who does?) exporting to a game engine can feel like a minefield.
That's why we created Game Rig Tools (GRT)
I spent countless hours testing different ways to export characters from Blender to Game Engines. And when I figured out the most reliable workflows, a coder friend helped me automate them and compline them into this Blender addon.