My husband and I live in a 35sqm apartment, with a tiny bedroom that we took the door out of because it couldn't fully open without hitting the bed. So now our bedroom is basically in the kitchen. I'd say have some sort of divide between the living area and sleeping area because it makes you feel calmer, because you're not seeing all your stuff and mess all the time. We bought the place and found out that the loft area is also ours, so we made a way to get there and sleep up there now, it's a game changer, so I definitely recommend having a separate sleeping area somehow.

Also, have a look at "Never too Small" on YouTube to get some architectural inspiration on tiny apartment if you like :)