I would suggest a built in bench, could possibly have some storage under the seat with room for 2 people at a minimum, float a table in front of that, you'd easily have room for 4 chairs (2 at ends of table and 2 opposite banquette). The bench would be a great place for you to incorporate color and pattern with fabrics on the cushion and possibly throw pillows. It's hard to say for sure, but I think you might still have room for a skinny island to float in the center of your kitchen. Once the table and bench are in place you could always add that if you feel it's needed. You could incorporate storage on either side of the bench seating similar to this:
You could do a great grouping of art over the bench seat which will incorporate more texture, color and visual impact.
You've done a wonderful job so far, keep up the good work!

I would definitely go with a multifunctional island. I have yet to meet a family with an island who still sits around the table. People love gathering in the kitchen whether just family, friends, or a whole party. You could probably still fit shallow shelving on the wall.

A rustic, multipurpose kitchen island in different materials or color than your kitchen could give you the feeling of a table, yet provide a workspace.

Here's a Houzz link to "rustic kitchen island." https://www.houzz.com/photos/rustic-kitchen-island-phbr0lbl-bl~l_42460

I like the island idea, rectangle long side parallel to the wall.I would remove the dining table and chairs and replace it with counter stole(comfti one).
Definitely some art work on the wall based on your taste, could be even a chalkboard to write the family weekly activity! I see lack of fun in your kitchen, everything looks perfect but create more fun.
Good Luck