Check with your local municipality first as to what will be allowed. A secondary dwelling unit is not allowed in many many locations. Then, if allowed, you will need to operate under the rules that do allow them. Many do not allow kitchens, etc. If everything aligns correctly, the largest obstacle then will be the plumbing. That is when you get an experienced plumber and builder in to address the limitations that adding plumbing will have on the design. You are way ahead of yourself. You don't know the constraints yet.

This is rough since I don’t have any measurements but this is concept. Creates bit of separation from bathroom and cooking eating area. Create a entry with Ikea closet at entry. Then a small cabinet behind sofa as a drop zone. Move table to other end and it serves as prep space and eating area. Hunt resale shops or on line for inexpensive corner cabinet for extra storage and possible display items. The tv would work best mounted on wall with pull out mount so everyone can see in the space. You could put table right up against wall to make more space for sofa and chair. Just depends on how many you have chairs or stools for everyday at your table. Try this for a week or so. Changes are always hard to get used to. Hope this further inspires you!

I would suggest a small scaled sofa (scaled for the space) on the long wall, and float the tv. https://www.wayfair.com/Williston-Forge--Solid-Wood-TV-Stand-for-TVs-up-to-55-X111677938-L6-K~W000566827.html?refid=GX444236625790-W000566827_824255789&device=m&ptid=902647982793&network=g&targetid=aud-354999624471:pla-902647982793&channel=GooglePLA&ireid=75415605&fdid=1817&PiID%5B%5D=824255789&gclid=EAIaIQobChMI_4mDnoq76gIVBMDICh31uQ7SEAQYBSABEgKEuPD_BwE https://www.wayfair.com/furniture/pdp/ebern-designs-jankowski-tv-stand-for-tvs-up-to-75-tdi10000.html?piid= https://www.potterybarn.com/m/products/williams-media-console/?gclid=EAIaIQobChMI34TcpY276gIVi5yzCh3mBg9eEAQYASABEgJQ6PD_BwE&catalogId=84&cm_ven=PLA&cm_ite=4204561&sku=4204561&cm_pla=Furniture+%3E+TV+Stands+%26+Media&cm_cat=Google https://www.overstock.com/Home-Garden/Furniture-of-America-Royce-Industrial-60-inch-TV-Stand/9914811/product.html?TID=SUI:FP_DETAILS

Decorating your apartment can never be easy as it must be balanced and attractive at the same time. You must be very choosy about the products you plan to buy, as they must be spacious, stylish and worth your money. For me personally, my design is completely satisfied. I remember how I was tormented until I found a good minimalist apartment checklist and how pleased I was with the result. These are simply indescribable sensations that everyone should feel. It is not necessary to have a large apartment for it to look inviting and cozy. You just need to be creative enough to make small spaces shine when it comes to decorating your home.