ST actually sells an evaluation board for learning about drone control; it has a BTLE module, four small FETs, sensors for pressure and a 9-axis IMU, a 1S battery charging circuit, and source code for some example firmware on Github. Search for 'STEVAL-FCU001V1'.

I've also seen a lot of cheap STM32-based FCU boards from the same places you'd get one of these 'blue pill' boards.

These are very useful chips to learn about, because they come in all shapes and sizes. Some focus on power efficiency, others on speed, others on connectivity or signal processing, and there aren't too many differences that you need to account for in your code.

Also, you can program and debug these using OpenOCD with a generic "ST-Link" module; they only cost a few bucks from cheap sources, or many of ST's evaluation boards have a built-in STLink probe which you can use. That lets you connect to the chip from GDB and step through your code like a normal C program, which is often a lifesaver.