Could you provide a 360 view of the room? Are you willing to swap out the table and chairs? Do you own or rent?

I was not aware “oversized clocks” were over. But, I had oversized wall clocks before they were “in”. If you like them and find one that you really like, go ahead & use it. IMO, it’s something that adds your personality to your space.

Large island...got it! My suggestion would be to store the table from your parents for now and focus on that area as your coffee bar/sitting area. By moving the coffee bar to that area, with two comfortable chairs, It will open up the space and eliminate your congestion concerns. For a more casual lifestyle with kids, such a large island is awesome for dining...especially since it seats six. As to what to do with the walls, I would suggest painting just the two walls in that corner a lighter color than the other walls, to brighten it. Don't know how far it goes...you'd need a natural stopping point, like another corner. I agree about the large clock...artwork suits your taste in the greens and creams with some bold accent colors would be enough to create a quiet spot for morning coffee or a glass of wine while cooking,

I would place an easy to read clock over the door in the kitchen. Dining rooms are not the place to locate a clock, large or small.

I would replace the mirror with another view............a framed landscape of some sort to enhance the perspective in the dining room and make it visually appear deeper.

Love the landscapes! Perfect for the room.

These canvas prints are available from a variety of sources. Keep in mind that some offer more sizes than others. Search by artist and title.

https://www.art.com/gallery/id--a8087-c23945/allen-friedlander-decorative-art-prints.htm

https://www.allposters.com/-sp/Reeds-Birchs-and-Water-I-Posters_i9724508_.htm?AID=96280778&gclid=Cj0KCQjw8MvWBRC8ARIsAOFSVBWhU0d0R_alj503jk673IVQMX1nXpEUumtPs5L1BWp8pS-7Aej1z3gaAprTEALw_wcB

https://www.greatbigcanvas.com/view/tuscan-valley,2123121/