Earlier quoted context omitted.
For cookie clicker and factorio the math was simple enough that you could mostly do it in your head, plus each of them had wikis that spelled out all the answers. I think you only really need a spreadsheet if the numbers are dynamic and continuously changing depending on your situation.
In Factorio I just let things buffer on belts and eyeballed things as I went along. The hard part was designing things such that I could arbitrarily scale out builders/belts as needs changed. Satisfactory requires you to be slightly more intentional with ratios but (at least when I played) I came up with some balancing belt designs that let me get away with not needing to be super accurate with matching input/outputs…
But at least with Helmod it’s still in the game UI. Using a spreadsheet seems too much like work.