I thought, the Peripheral library is deprecated for STM32. Is there any reason to use it besides the STM32 CUBE framework?. Because, the later seems to support more STM32 product lines.
Stm32 cube mx is the newest version of the framework, but the old peripheral driver library is a bit simpler and easier to use! It is more low level and a light layer over the hardware.
The new cube libraries do include two abstraction layers, though. I agree that the "HAL" libraries can be very confusing because they try to do everything for you with endlessly nesting functions and macros, but the "LL" (Low-Level) ones are closer to the old peripheral driver libraries.
The new cube library can be more complex.