Looking for resources for learning STM32 from the ground up

If you are designing for video game controllers, Arduino IDE for STM32 won't cut it. People complain about Cube, but it's free. It's true that third party IDE's may be better, but Cube itself is miles beyond the Arduino adaptation, and I have a feeling from your introduction, that it's all you will need.

As far as the complaints about too much documentation... well... seriously? This is engineer level work.