Farmhouse old chimney

Hello, it’s about the following "problem": - old farmhouse with tiled stoves and old chimney (there is still a second one, which is OK, there is only a small stove attached to it where the pipe still goes over the hallway :-/, we still have to clarify if that is STILL possible.....)?! - chimney sooty from the ground up and crown crumbly - 2 tiled stoves should be reattached there and a large "new" kitchen stove (Glutos, has been standing there for 20 years but still wrapped in foil!) and put into operation (house extension planned for living) - so far there have been three opinions :-/ a) renovate from the ground up and repair the lower part with concrete (we were at 5000€) b) completely new (however, we would like to avoid breaking into the living rooms) 2000€ c) insert stainless steel pipe into old chimney and connect stoves to it (this variant we like best!) only who approves that, chimney sweep was quite unfriendly on the phone and wanted to talk us out of everything :-( Now we are confused because all 3 variants cause different costs..... What can you recommend???? Does anyone have experience with this???? House is from 1875! Grandparents moved out early 1980, I believe..........! Since then it has been empty, but is used for storage and chicken coop and saddles etc......... but otherwise unused, in winter we heat the OLD kitchen stove (small Glutos) so that feed (soaked) does not freeze and the water pipe - no smoke in the rooms - smoke comes out normally at the top!!!! We want to start soon......... - chimney straightened, then a second inner wall raised on the weather side for insulation (we are not allowed to on the outside!), then new windows and the old smoke chamber at the old bedroom should be converted into a bathroom (connect and lay pipes etc......) We come from Saxony (Colditz), maybe someone knows someone who can help us!? Thanks