If you want real organic soil, make sure to read every letter on the packaging, especially the small print, regular soil contains synthetic fertilizers. Look for a certification logo, like you find on organic food packaging.
That, mixed with amendments like basalt, seaweed powder and malted barley will do the trick. A cup of each per 10 L of soil is a good start. Many would add perlite or something similar as well. I think it’s a waste of space for nutrients if you’re not in a very humid area. When going no-till, the roots from the previous grow will provide aeration along with worms and insects.
You can use vetch as cover crop. Sow one bean along with every plant.
Dandelion, thistle, nettles, grass, tree leaves, kitchenscraps, etc can be cut up and mixed with the soil too. Especially banana peels (potassium & phosphorus) and dandelion (10% calcium) are great.
Inevitably you’ll get insects, no matter what method you use, it’s all part of the game. Back off on the watering, it’s a mistake most new growers make. Water less than you think it needs. Don’t water every day. I only water once a week or so.