Maybe on topic, maybe not. Have you looked at the analysis of compost, the bags they sell at the big box places. The P-P-K. What I typically see is 0.5 - 0.5 - 0.3 That is not real rich in nutrients though it helps. To me the big benefit to compost is how it textures the soil.
Its most definitely on topic.
I stopped looking at things like 'proper ratios' a few years ago and did try to just recycle my own organic 'waste', trying to apply the law of return.
While I do buy the odd bag of compost and more often, potting mix. Its usually mixed with my own soil to get the seeds/seedlings started in Spring.
My soil is supposed to be volcanic silt, to me, its sandy, too free draining and sucks up organic matter like it never happened. Its been an on going experiment to try and get a good mix.
One of my telling points, is weather or not the slugs and snails decimate my seedlings. I decided that if they do, then I didnt get it right.
I know its sounds rather odd, but I no longer hate slugs and snails for eating my seedlings and plants. I now see them as a needed and useful part of the eco system that is there to remove plants that are somehow deficient and have no value genetically speaking.
This year,for example, with my Cannelini beans, i saw them remove what even I could see was struggling seedlings, but leaving those right next to the eaten ones. I did have to sit and think about this before deciding what i was going to do about it.
I decided to do nothing. I have native lizards in my back yard now and know that they just love them.
What I am trying to do, is get my little ecosystem in balance with itself and understand that it will take time.....and that I need to watch and learn, rather than just react.
I have problem plants-privet for one, that I just cut up and use as mulch, before it sets seed.
I do try to cut it up so it lays flat, then try to cover is all with things like lawn clippings- this year thats been mainly from mowing my mums lawns or from my neighbour who is only too happy to get rid of 'that stuff'. My lawns re so small now, that I just dont have enough green waste anymore.