I'm sure that lawn isn't doing the topsoil any favors. I'd recommend tilling it up, growing out some fat straw and cannabis to add some fiber to the soil, then start by straw bale gardening.

Permaculture is likely where you want to be and that means animal husbandry to do things smart and low effort. Cycling chickens and cows and maybe pigs through land you are remediating before your first grown or after a grow is important. https://www.youtube.com/results?search_query=polyface+farms+animals&page=&utm_source=opensearch

Crop selection is obviously important. Selecting based on ease of growth, expected profits, and local competition are all factors. Hell, aquaponics might be the way to go and then you can skip all that soil remediation and much of the animal husbandry while saving lots of water and eating lots of fish. Best of luck to you!