It’s not that bad. Definitely fixable and most houses of that era might need the usual cosmetic work.
The red shed looks like it might have a sex pond in it with windows for the neighbours to see in 😜. Get rid of that, the decking and fake grass. Add some pillars to support the upper balcony and create a faux lower balcony with some nice patterned floor tiles. Some sympathetic landscaping and it would look transformed.
I think there might be space to create a small narrow window in gym making it a more versatile living or bedroom and add value for a very low cost.
It reminds me of Shnordic (insta) home. Pale wooden flooring throughout and loosing the magnolia will give an instant lift.
Kitchen and dumb waiter not really to my taste but looks quality. If it’s a German brand you’d likely be able to swap out the walnut doors for something else for a a couple of grand.