The PSOC series def has some good documentation and some really unique features, but by good lord the IDE sucks and it does not do the basics well. The PSoC is like Andy from the office (he graduated from Cornell), the whole experience is defined around the "cool" thing called analog blocks, if you want a Cornell graduate MCU with analog blocks there's literally nothing else like it, but if you want a good general purpous MCU look elsewhere. Double- oh god no -for the PSoC6 it looks capable but everything about is half baked, even the PSoC IDE did not support it properly.
There's STM32, its a steep initial hill to climb but once you are on top at least ST is consistent. Also use LL drivers HAL is waste of time.
Now, some people are going to skin me but consider the teensy series, aka Arduino for grownups. It is literally just Arduino in name. You want something to just work, hey you can do that fast and easy with a very well documented and written code base (SPI, UART, printf). You think that you can write better code or you want to eek out better performance go arount6 the provided libraries, hell just re-write them they are all just NXP microconrollers. NXP datasheets are okay, the peripherals don't have the kitchen sink included (like ST) but hey it will work for 90%+ use cases. Just check out PJRC forums the core team is very very helpful. They have 4 Microcontroller options(LC, 3.5,3.6and 4.1), if you want to migrate your project down the road to an actual product just use the same code and build a new PCB. Just a note DO NOT INSTALL THE TEENSYDUINO/ARDUINO IDE, its built for kids. Use platform IO + VSCode (FREE) endlessly customizable and supports some really advanced stuff with just add-ons