Both images look quite nice. I love the sky in the top image. The only issue I have with this ine is that if this was the actual colour of the sky it may reflect similarly in the sea. It seems like the ND grad may have been too strong. A tint of the sea may match it up.
You could have used two ND grad filters, a stronger on the sky and a lighter on the sea, but I think the complementer colours actually make the image very nice. Nice composition on both and perfect exposures. I love the blue on the second one. Isn’t the second photo tilted a bit to the right?
Excellent work!