PCF8591 has one 8 bit ADC on board for 4 channels. The ADC is 8 bit and quite fast. At 100 KHz one gets more than 2000 reads per second for read() and more than 2000 writes per second for write().

There are different ESP32 Audio boards available that can be programmed with the Espressif ADF Framework. The ADF Framework contains an abstraction layer to support different codec audio chips (ES8388 ...