>>I would like to program the STM32MCU in assembly language.
And is something stopping you from doing this? Primarily using Thumb code, example of code/structure can be seen in startup.s you can add to that.
Are you a book learner, or a video one?
Might suggest you find a book on Cortex-Mx coding, or ARM/Thumb in general, and then pivot into a specific implementation. The Reference Manuals should cover peripheral addresses, and registers within.
