I must admit I think the US has huge geographic and social diversity and choices in ways of life, etc
The kind of retirement life you might have in Memphis is different from Asheville, from New Hampshire, from Brooklyn, from Portland, from Arizona, from Nevada, from Hawaii-- and even between the islands in Hawaii.
Now I understand the generic concerns -- healthcare costs, taxes, crime.
Other countries have similar issues. Healthcare here (UK) is free at point of dispense BUT there are issues with waiting and generally the more interventionist forms of treatment are often not practised. Crime? We have less gun crime than you do, but plenty of breakins, pickpocketing, theft from cars and anti-social offences. As you get older that can be quite frightening-- graffiti, kids being rude or hostile on the street, road rage etc.
There are people who prey on old people in every country in the world, alas. Conmen, criminals, people who 'know best' and do not accord the old respect and the freedom to make their own decisions.
Many Brits move to Spain for the weather. Many regret it and wish they could move back, but can no longer afford the housing--- particularly in very old age.
Dealing with Spanish healthcare and social services, even if your Spanish is good (most Brits live in little enclaves associating mostly with other Brits) is difficult.
I dread the thought of living in some little expat enclave bitching about the locals, hanging with other expats. But I don't really speak any foreign lanugage adequately.
If you have grandkids or family being a long way away from them becomes more difficult as you get older, especially if your partner becomes ill or dies. A lot of couples move to Spain, one dies, the other is terribly lonely. What if one of you requires institutional care?
In other words, living for a few years abroad in retirement is not a bad plan. Or do house swaps.
But in the end, is the USA not a diverse enough place that you can find somewhere there that meets your needs?
I write this having a morbid fear of 'retirement communities' like you get in Arizona, say. But, who knows, maybe some day that will appeal more, as my ability to live with the chaos and challenge of daily life in ordinary cities and suburbs diminishes.
Someone once said, wisely, that if you don't find meaningful hobbies and commitments in retirement, you became an 'old person' basically complaining about your health, and about various nefarious plans by government or your relatives to get *your* money. Even subscribing to conspiracy theories.
You don't want to be like that. Until the day of his untimely accidental death in his 80s, my father was a man who walked every day, who was engaged in civic planning meetings, talks and dinners at the university, geneology, hhistorical association etc. A man I could spend an hour on the phone to talking about current events and challenges in energy, politics etc.
All I can say is this. Try to be near friends and family, or at least where you can reach friends and family. And mental stimulation: be it sports, libraries, culture.