I would just remove the windows, and leave that opening open, if you insist on open concept. I have to be honest here though, and tell you, I detest open concept, especially when it involves a kitchen area. I do have open concept between kitchen and dining room, because the house was built that way, and there is no good way to put a wall up between them, or I would have done that long ago. I cant stand looking at kitchens from other rooms, and I would never buy another house that had the kitchen open to other rooms.

The way its framed indicates its not load bearing as there is no header above the door- if it was framed right. The problem is it may have been put in by someone who just didnt frame it in properly. Can you go up in the attic and see how your trusses/rafters are supported in this area?

Is this one story house? A ceiling to roof installed Solatube would bring in tons of natural light & they can also have electic lights in them for night time, That means you can use the ceiling hole for an existing electric fixture & swap for a Solatube. I have both kinds in my home. Much, much less $$ that all the dry wall work needed for window & less drastic than losing wall space. Here’s a 10” tube in my kitchen with all lights on.. Here’s lights off. My kitchen has no windows - adjoining dining area has north & east facing windows with very tall 90’ at least Douglas Firs on adjoining property blocking morning sun.

IMO you need a steel beam and as for the floor once you have opened that ,all this space becomes all one space so all the same flooring . If you want the beam embedded so it is invisible that will cost big $$$$ and sometimes not possible. That is why you need a good contractor and IMO a structural engineer to tell you what can be done and how. Your walkways in the kitchen are too small and remember if the beam stays visible that space really did not change if you could not have an island before visually you still can't have an island .You also need an independant kitchen designer since there are IMO some issue s with layout.