Ideally, you'll want to position the window at the correct height, but understandably it might not be easily remedied. Trimming the window should probably somewhat match the other window trim in your house. I think removing the apron is fine and is a common practice; certainly it will be more practical with tile in that space. You might explore beefing up the size of the current stool as it seems to be on the thin side--not sure if this is important though. The one thing that stands out to me is the oversized width of the horizontal header trim above the window, which seems to be making your window appear more wide than tall. I think the header trim should align with the width of the side trim rather than the stool. Craftsman style trim would work if you want to balance the header with the stool, but wondering again about the other windows in your house coordinating.

A pendant light or a sconce could also help with the situation as you suggested. Here is one example of Craftman style window trim. https://www.thenavagepatch.com/diy-craftsman-style-trim-for-windows-and-doors/

"My kitchen window was installed 3" lower than what's in original design"

Was it installed to line up with the balance of the exterior windows?

I actually like windows installed as low to the counter as possible. Much better view. However, I would put granite behind it as well as a granite window sill and let the side trim of the window sit on the granite. You wouldn’t have to carry the granite under the window beyond the width of the window. I know many look at short back splashes with horror. I am just talking about under the window.

It looks good from the inside. How does it look from the outside?

I agree with @Nancy K. When we replaced our kitchen sink window we intentionally made the new window longer, so it would sit closer to the countertop and increase the view and light, I think we have about 4 inches from countertop to bottom of stool. We will not be adding an apron, just tile underneath.