Hi, author here. I must say I'm not 100% confident in everything the STM32s do - and the rp2040/rp2350 is an easy one. One of my pieces of work is : continuous acquisition, acquisitions, processing, and writing on a fast storage, which allows for continuous 10MB/s+. All of this can be managed through the 2 cores, and the PIOs.
In short, PIOs are really a game changer, I have dumped a FPGA from the previous iteration to go rp2040.
BUT... solutions like some of PIC32 and their integrated 40Msps ADC are really nice and worth exploring (if I had the time). The positive thing about the pico is that it's so common and tools are so common that it's really a pleasure developping on this device =)