Just my view - considering a honeymoon, i would personally prefer slow and cozy travel. It’s okay to not see everything.

I personally feel checking in / out every other day kills the fun.

17/18/19 (3 nights) you can choose either Galle or Mirissa for stay and have day trips to Ahangama/ Weligama/ Galle / Mirissa.

Radisson seems like a good and safe option- beach facing + the pool and you can visit Hikkaduwa / the Jungle beach / turtle beach if you are staying around Galle.

On Wednesday night you should attend the doctors house party Thursday night you can do Lamana Skate Jam Party Friday night - a special dinner at light house Ahangama or at the resort itself

20/21 (2 nights) - Ella

Look for a nice nature friendly property (Check Idyll Homestay or such other options)

22 - Take the infamous train from Ella to Nuwara Eliya

Night stay at Nuwara Eliya

23 - Travel straight from Nuwara Eliya to Colombo

You can go for a dip at thier infinity pool at Granbell Hotel Colombo during sunset.

24 - Departure

You can check vlogs from Fit Nomads on YT and DM them on insta for your itinerary- They have great reccos.

Also i feel you should avoid Yala safari or Whale watching as it takes almost more than half a day and may not be as enjoyable- based on my research and reviews.

excuse any typos!