Just for discussion purposes.I picked this pic off the internet.It looks like a lot of "Hoarder Houses" decor style.Busy carpet, busy furniture, paneling, faux rocks on the walls, flat paint.I can smell the cigarette smoke just looking at the picture.But I wonder if you owned this place, as either a flip or a rental, or AirBnB, would you rip everything out and paint it all grey and modern.Or do you think pic 2 is acceptable and cheap (quick) way to do it.Tear it out to the studs, or just light cosmetic changes, or something completely different?

Also you can notice that rubbery material, I was thinking of  ripping it off and replacing with a new one but not really sure what product I can use to replace it.

Begin by taking down walls and ripping out cabinets in the kitchen.

One thing they did was diy stain the concrete slab after they ripped up the original hardwood (I could slap them).

so you need to find a quality GC that wont rip you off

I would rip up the worst areas of the particle board maybe all of it and replace it.

I'm fairly new to BP, so please feel free to rip into me in the comments. 

I experienced what ripping up multiple floor layers was like.....miserable.

My eye is on hard money lenders but I have a hunch that some of these people reaching out are not legit or are trying to rip me off.

The bigger, main level unit is not livable at the moment (Flooring all ripped up.