8bit controllers like AVR a lot more accessible if you are going with no arduino approach of just datasheet+compiler. All the peripherals are described in single reasonable size datasheet and you can don't need much hardware initialization code except for features that you directly use. Bringing up an ARM chip from scratch without using a generator like STM CubeMX or a frameworks like Arduino with existing hardware support packages will take a lot more effort.
Yes, if you're doing that. Which is why I said "if you're staying within the Arduino ecosystem"
I've been programming embedded systems for-fricking-ever and even I stay with Arduino libraries if I can get away with it for non-critical projects simply because it's easier.
