Microcontroller ADCs still have a bad reputation compared to "hardcore" analog designers, but STM32 isn't bad in the great scheme of uCs.
https://hackaday.io/project/188051-rpscope
Here's the original project, and with a circuit layout closer to what I'd expect to be typical. However, notice that the STM32 contains all the parts that are in the rpscope: STM32 has an ADC (albeit a slower one), multiple OpAmps (albeit with lower accuracy), and a microcontroller (albeit with less RAM than the RP2040).
Shrinking and consolidation is the goal for these devices, leading to far cheaper designs with possibly better reliability (now that its all put together in one package). Of course, the specs are far weaker on the STM32 rather than dedicated ADCs, but you can see the size, cost, and power/watt difference by just looking at this thing.