How to make cookies consistently the same?

I’ve been working on some cookie recipes recently. My family thought they’re really good and even suggested selling some, and since I was already planning on opening a shop I’m hoping to get them ready for sale. The only problem is I can’t get these consistent for the life of me! They come out relatively similar in taste, however there’s always a slight variation. Sometimes they’re slightly sweeter, chewier, softer, thicker, so on and so forth. The strangest part is that there’s a lot of variation between how long they take to bake. Sometimes they take up to 15 minutes, while other times they need just 11.

I’ll admit that I don’t level my ingredients, but surely that shouldn’t cause so much chaos? I’m worried that unless I could recreate the recipe perfectly each time, I can’t open a bakery since I won’t be able to sell the same product each time