10 day trip to Srilanka- recommendations required

Planning a 10-day Sri Lanka trip in October 2nd half with my wife and our 2.5-year-old child.

We're looking for a relaxed beach segment towards the end of the trip—more for scenic views, good food, sunset walks and a nice resort atmosphere rather than swimming or surfing.

From what I've researched, October seems to be a transition month weather-wise, so I'm a bit confused between the South Coast (Mirissa, Tangalle, Hiriketiya area) and the Southwest Coast (Bentota, Induruwa, Ahungalla, etc.).

For those who know Sri Lanka well:

* Which coast generally has better weather and sea views in October?
* Which area feels more relaxing and less crowded?
* If swimming isn't a priority, which coast offers the best overall beach/resort experience?
* Any specific beach towns or resorts you'd recommend for a family with a toddler?

Current itinerary is roughly: Nuwara Elita → Ella → Safari in Udawalawe → Beach stay (3-4 nights).

Would love to hear your recommendations. Thanks!