I've taken over part of an old abandoned field earlier this year of my parents and moved here with my 2 daughters (7&

. I came home to heal after some trauma, and to be here for my parents who are aging.
I'm concentrating on an acre of it for now, but there are another 3-4 if I have the time/energy.
My area has 4 concrete paths running north to south equally spaced, and another few overgrown gravel paths belong this. Most of the land is a mixture of nettle, thistle, ragwort, reeds, dock and buttercup. I have a static caravan across 2 of the paths. I've added in a natural clay lined pond with land drainage running in and out as overflow. I erected a poly tunnel and shed and have a cabin to rebuild.
I read somewhere on here that sometimes plants grow in a particular place as the land needs an element that plant brings. So what do I keep, what can I get rid of, is there a way to find out what the land needs? If there any use in harvesting these? They're all about 2' high at this point.
In the places where I have cleared and kill mulched, a few weeks later the 'weeds' are pushing through just the same regardless. It seems to be a never ending slog.
There is lots of wildlife, particularly frogs, toads, slugs, snails etc. I was hoping by coming here that I could help heal this bit of land that hadn't been taken care of and improve it. But it seems whatever I do, just either causes harm to the wildlife or it reclaims itself to it's overgrown spiky stingy mess asap.
I'm in North England and feeling really very disheartened by the whole thing.