Oh god so my background is CE/ECE stuff and you managed to trigger me. I don't want to be rude... just bluntly saying you triggered me. Doing something really small for A/D D/A with 8bit and not worrying much about resolution and data loss is one thing. For something massive scale the problem is a lot less trivial and a lot more mathematical.
[1] https://protosupplies.com/product/pcf8591-a-d-and-d-a-conver...