My current grow in my signature is with FFOF amended
“Full of nutes” isn’t really a thing in organics the way you’re thinking of it. The “nutrients” aren’t available to the plant in their bagged form, it’s stuff like EWC and guano, so the same stuff you’d be amending in anyway. Unless you’re going to be doing soil tests with a lab to tweak your values, a “neutral” soil isn’t going to do you much good.
The best base is a cheap, high quality organic potting mix like fox farms ocean forest or G&B Blue Ribbon blend. You don’t want to spend crazy money on a base because you’re going to be doing so much amending it’ll be a waste to go with something like Stonington blend. Cheap and organic, that’s it.
“Curing” the soil is actually typically called cooking which is actually just composting. The length of time it takes depends on temperature, oxygen and water. At 80F it takes my mix 45 days to be ready. I keep it moist and turn it every couple days. Colder temperatures will take longer. Less oxygen and too much water or too little water will also take longer.
Never, ever, EVER, amend a soil with minerals and inputs then use it without cooking. You will overwhelm and fry your plants. The microbes need to work on those inputs, locking them up in their bodies and poop so it’s in a form that won’t overwhelm the plant.
You’re looking at around a 45 day minimum to cook the soil for use. Depending on how powerful your mix is and what your temps are this can vary widely. Some peoples mixes take 3-4 months to cook, mine like I said, is 45 days. I could get away with 30 but there’s no need.