Install new windows at counter height. If you block these windows with a counter you won't be able to open them. Or, put your sink on another wall.

I think this is pretty cool but probably not cheap

Changing the height of a window means replacing the window with a shorter one. It can be done, but you'll still have the bay space behind the sink. And that sound like a hard-to-reach, hard-to-clean recipe for clutter and grime.

The changes you are considering may look easy on paper but will be expensive and time-consuming in practice. My friend priced a similar dining/kitchen flipin a relatively small home-- flipping and renoing was estimated at $120k vs $40k for leaving things approximately where they were.

Have you engaged a kitchen designer (not a cabinet seller) to help you find potentially more effective/cheaper solutions to your kitchen issues?

Replace the window with one that works in your new design.

Lots of moving parts there now moving all that plumbing. Hope that you are on a crawlspace or have an unfinished basement.

And when you put a smaller window, hope you can match your siding. If it's a natural product, like cedar shake, you're probably fine. If it's painted Hardie board, also okay. If it's older vinyl, aluminum, or discontinued brick, you'll have a problem.