Living very frugally, and driving an old car, wouldn't bother me but living in a Soviet-style flat would seriously depress me. Maybe it's having an effect on your own psychology? Human beings are by nature outdoor animals and living in a huge block apartment is about as far from the natural outdoors as you can get.

You could try renting a proper home on Airbnb for a month and see how you feel after a few weeks of having a nicer environment.

This is the main reason most Americans want to own a home with a backyard. It allows you to relax and BBQ in the "outdoors" any time you want. Sitting around a fire pit is soothing in a primal way. I think most people find that it improves their psychology immensely.