So it turns out that you can even find the JDY-08 breakout from Aliexpress, which means that every part of this project is now easily breadboard-able! This means that even if you don't know how to solder, you can also build a measurement circuit yourself.

Since this is meant for low voltage experimentation, it can only measure up to 3.3V. Using Arduino's native ADC which gives us 1024 counts (8-bits), if we increase the voltage range we can measure, the precision falls.

Maybe one way is to create a switch so that you can turn on high voltage measurement whenever you want to, although I think that might already be a feature creep.