How do I clean this up!

We bought an old farm that sat for 20 years being used as summer house. We are the third owners. The place was filled...and I mean FILLED with so much useless crap. The yard was grown up. The barn was full of crap and is dilapidated. Yes, there was floor damage under the Pergo someone tried to put over the rotten wood. OK. But it came with 6 acres of land with lake rights, it had a well, a nice brick oven in the kitchen. I can deal. We bought as is.
It took months for us to get everything out.
Then we discovered the minor floor repair needed in the log house was actually rotted sills (2) on the exterior logs and interior logs. We're talking 40 grand if we want to live in the house. The 2nd owners completely enclosed the bottom of the house without proper ventilation. They poured concrete in the kitchen, hall & sauna. Apparently placed a vapor lock or something backwards so that all needs to come out. They built an indoor sauna. Our sauna has (no shit) 12 corners!!! They put a toilet in without water. I think I might start crying going through this crap again.  The nice brick oven wasn't built properly so the smoke came in the house instead of up the flue. It took 3 months for me to dismantle it. Only because much of the mortar was soft.
I started having health problems because of the mold so we had to buy a used barrack to sleep in and keep our clothes.
But the thing that totally boggled my mind, was when we hired an excavator to do some digging. There is garbage, plastic, metal, glass, clothing all around the property. In the middle of our forest, we even found an old plastic shopping bag with plastic food packages inside. I found 4 disposable shavers pocking out of the dirt. Our neighbors said that's just the way people lived back then. WTF
I have no clue how to handle this. Every place we dig, there's plastic or glass. I think the dream of living in our own little permie world is just a dream.
I'm not looking sympathy, just some opinions on what can be done.

It sounds discouraging and bewildering in the present tense, but I can easily imagine reading a follow up post from you, sometime in the future, wherein you talk about how overwhelmed you were AT FIRST, but how you overcame it. It may be hard right now to see into the future, and it may be annoying to have people like me telling you it'll all work out, but many of life's challenges seem insurmountable at first.

I'm not sure what to say about the garbage everywhere. But my first thought on the house is to build a wofati. If you can arrange a workshop it could be built pretty cheap by making the students pay enough to cover material and excavator costs. I believe that once you have a solid house everything else would probably seem less stressful.

I dunno what to say about the house, but you've got a safe mold free space to sleep. That is a good thing.

The neighbors aren't wrong about the leftovers from the trash shedding, many rural spaces people were responsible for all their trash disposal needs and they either burned it or just dropped it where they stood. You might also find a couple spots where they dug a hole and piled it in for a while, then covered the hole.

When I've been working garden space that had sheddings, I'd keep a bag or bucket with me and just gather them up as I went along. Think of it like weeding or washing dishes, it's not something that can be truly finished, but you'll get a good bit done today. Six acres might be way too much to face today, but if you focus on just one small area, maybe right by that one window, or that corner right there... that's doable.

If they're reasonable for your climate, consider adding a couple gardens that build on top of the existing ground (keyhole, raised beds, a collection of pots.)  Or things like a rock garden or some hardscapes - you might well find a spot or three that are more broken glass or sharp metal bits than you're up to dealing with, and it might be safer to entomb it.

When motivation struggles, turn it into a bit of a game. Maybe take a picture of your gatherings each day and show it off! Or weigh it and share something like "Today I got 2.3lbs and this red plastic spork!"