Our previous kitchen diner was about that size overall but with a big corner taken out (it was an L shape rather than a rectangle). We had kitchen (with a small island), large dining table (90 x 180) and seating area (with sofa & tv etc). The only thing to say is that we were lucky with door / window placement but did brick up one door so we could put a sofa there, or it wouldn't have worked.
You definitely be able to get those things in a room that size.
My kitchen is a bit smaller (5.6*3.9). I think with the extra bit of width and length, you could have a kitchen with an island and decent dining table. Not sure about fitting the sofa in though. Or possibly yes but it might look a bit odd just plonked into the kitchen - I don't think you could have a kitchen, dining area and a proper sitting space.
If you fancy something a little comfier to sit on than a kitchen chair, you could use a bench or a banquette. We have one as we've got a tv in the kitchen so it's nice to sit comfortably with your morning coffee and porridge and catch up on the news.
I've got 7m x 4m. No space for a sofa. The kitchen area is about 4x4, and the eating area is about 3x3, including dressers. If we swapped them around, we would have space for a sofa in the dining area. But I prefer the bigger kitchen.
Ours is 5 x 7 with extra deep worktops (70 cm) wide gap to island (120) and deep island (90) we also have a wide dining table (100) - we have a sofa as well currently and it is "cosy" but not ideal. With your space if you had less deep work tops and a narrower table and no island you would have loads of space.
We are now knocking through to our lounge which we never use so that it will be all one space (11x5)
Not sure which way to face the sofas in the new kitchen/dining/living set up whether to move the fireplace .... would be interested in experiences views - plan on this link here....