It might be time to start thinking about must have and nice to have. There's probably more than a few that would like a similar kind of place you are hoping to find. If they have found it, then most likely keeping quiet for fear of it being ruined by the crowds.I was thinking a place that has good weather during the Northern-hemisphere winter. I would probably spend summers in different countries in Europe (Greece, Italy, France), and then towards the fall I could migrate to a warmer place to have as my main base. Would be great if there were beaches and lots of green.
I find Singapore quite small/boring - it always feels a bit claustrophobic to me. Always feels like people only live there to work. It's also very expensive.
Hong Kong - absolutely love that city, but it's cold in winter. And rents are extremely high as well.
Panama, Costa Rica - Haven't been, but to be honest, I'm not sure I would like it. So far, I haven't really been a fan of Central/South American countries. I just don't really click with the culture. I think I'll go check it out in the future, but I'm skeptical.
KL - I've always been a huge fan, love how green it is, but somehow during my latest visit I didn't love it as much as before. The air quality can also be very poor, there's often smog/haze.
Japan - Absolutely love it, one of my favorite countries. I've even been thinking about moving there despite colder weather in winter. But it does get quite cold, no? Even in Okinawa. And I have been to Naha, wasn't that impressed. Only tourists and US military.
Taiwan - not a fan. And not really warm in winter.
Mauritius - see above.
Labuan - haven't been, but I guess it will be poorer than KL. Also doubt that tax advantages would be that great, as many tax treaties explicitly exclude Labuan.
Fiji - would love to go, main issue is that it's so far away, annoying to travel to and not easy with the time zone.
Sri Lanka - haven't been, from what I have heard, it is similar to Mauritius, so subpar beaches, quite poor, not very developed.
Cuba - not interested.
Thailand - Definitely one of the top options. Bangkok is great and there's a lot of high-quality real estate, services are cheap etc. Biggest issue is that I don't like the noise and pollution and it's not very walkable. And as soon as you go to a smaller place, it would probably suffer from the same issues again (less developed etc.).
Indonesia - not developed enough. Jakarta is a bit better, but I'm not a fan, it's just a huge city without much soul. Lots of malls and apartment high-rises. Bandung was a bit nicer, but again too small and not that easy to get to.
Vietnam - from what I've heard, Phu Quoc is very underdeveloped outside the 2-3 resorts. Also lots of garbage in the sea/on the beaches. I've been to HCMC and I found it boring/soulless, just like Jakarta.
Hawaii - didn't like it. Very expensive and difficult to find healthy food (USA). Felt like what the Canary Islands are for Europeans - a place you go to when you want nice weather. Nice enough if it's a 4-6 hour flight from your home. Not worth it at all if you have to fly for longer than that.
I would like to live in an apartment that has the build quality of an international five-star hotel. Think Four Seasons (they actually have residences in many places, so it's a good example).
Thailand and the UAE both offer this. UAE is more expensive. Both would be OK options.
But I know next to nothing about the Carribean, so I'm wondering if that could be an alternative.
Another option would be to just spend the winters in Florida.
Tax benefits would be nice, but I'm not that worried, as I would expect to be able to set things up in a tax-efficient way regardless, and I would be OK with paying some tax for higher quality of life.
There's also probably some places in Queensland, Australia that meet some of those requirements, however, you will pay dearly for them and cost wasn't a factor in your first post. Speaking of that, yes Hawaii has become very expensive and I can no longer justify what some are asking for their vacation rentals.
Florida became very expensive during covid when it no longer had the low season and the high season prices went higher. If you're fine with crowds, go ahead. I used to dread seeing the car transporters arriving around Thanksgiving... PBI used to be a pleasant airport (by US standards so a low bar) and now it's seems to be a mess all year.