First, given your goal of "[participating] greatly in local business and community," use language as a first filter. This question will either eliminate or open up most of the world: "Am I willing to spend 3-6 intensive years to learn a new language (and not be very effective during that time)?"
Near-native fluency isn't required to live somewhere, but it is basically required to make an impact there outside of any expat bubble.
Second, from that scope, pick any 3 cites that meet your cost of living requirement and live in each for a month. Airbnb makes this relatively easy. Aim for significant differences - continent if possible, city size, culture, weather, similarity to your situation now, etc - between the 3. The specific 3 cities matter less than ensuring you experience a month in maximally different situations.
Use what you like and don't like at those places to decide where to live/test next. After living briefly in 1-3 more places, you'll either have a strong, informed opinion about what you like (and probably a favorite place), or an unexpected result, like that you actually enjoy moving around, or aren't happy anywhere, or don't want to leave where you are.
(Source: I did something like this, though not with the goal of relaxing)
Put the money 90% in VOO and 10% in BND (like Warren Buffett tells his heirs). Or get fancier as you learn how to invest.
More (read the sidebar on right): https://www.reddit.com/r/financialindependence/
'participate greatly in local business' Your time and energy are probably the best thing you can give.
Bonuses:
- North Africa round the corner. Actually there are two Spanish cities in North Africa, so you don't even need another visa to step on the continent.
- You also have Huelva and the Portuguese Algarve somewhat close.
- Very cheap flights to anywhere in Europe (my last Málaga - London Luton was £24) and easy to jump to Madrid or Barcelona for long haul.
ER Cities in the U.S. - https://redd.it/3cjtth
The Reality of Expatriating for a Lower Cost of Living - https://redd.it/5w4p92
Where do you plan on retiring early? - https://redd.it/5kj438
It could be a path to mediocrity.
Croatia is one of the safest places I've ever lived. I think I'd rank it higher than Canada. I hitchhiked in Slovenia and all three times I was picked up by women (I'm male), once by a mother and her daughter, once by two friends, and once by a mother and her son. How many places in the world do women trust picking up random male hitchhikers? That gives you an idea how safe these places are to live.
You might like one or another, so choose wisely :) also Canary Islands are incredibly touristy (albeit there are a couple of proper cities, too) so "only English" won't be a problem in pretty much none of the islands.