AIO pins 0-5v reading 3.150v

[Honeybadger]

sensor is output 0-5v.
esp32 hardware is 0-3.3v.
so need config by esphome yaml, let 0-5v data convert to 0-3.3v signal is ok.

Let me see if I understand it correctly:

• The ADC sensor input is 0-5v
  
• Internally there is a step down from 0-5v to 0-3.3v (for ESP32)
  
• The data that we collect from Home Assistant is 0-3.3v and it has to be converted back up to 0-5v using some equation.
  

Is that correct or I missed something?

Question:
Is the ADC sensor good enough to measure millivolt changes accurately?