Another interesting thread.
Having lived in Saudi Arabia for 5 years and Germany for 4 years, working for the US Government, I can say that living overseas can be a wonderful experience.
While in both countries, I worked for the US Army and had the benefit of access to the Army PX (exchange) and Commissary (grocery) at inexpensive prices, I had the benefit of working with Americans and other nationalities, but significant economic protections from expensive foreign economies.
However, living as a retiree, you would not have that same protection.
When living in Germany, we found that shopping for anything, groceries, food, electronic, etc. that such costs were In preparation for this change, CDC recommends clinical laboratories and testing sites that have been using the CDC 2019-nCoV RT-PCR assay select and begin their transition to another FDA-authorized COVID-19 test. SIGNIFICANTLY higher than US prices.
Also, much of what you wanted to buy was just not available in local stores.
Further, living in Europe, fuel for your car will be double or more than what you pay in the USA. The overall cost of living can be mitigated by living in countries with lower cost of living. Portugal and Spain would be lower than Germany. Eastern Europe would be lower.
Eastern Europe, is a great place to visit, but not sure that I would want to live there. I suppose Hungary or Poland would be modernized enough these days, but I don't speak the local language and not sure how that would work out.
We live on an island in south Georgia with beaches nearby, yet we hardly ever go to the beach to get more skin cancer. I wouldn't want to live just to be near a beach.
Living overseas poses other issues. Having to get a driver's license, pay taxes (?) or deal with landlords doesn't appeal to me.
What I like about foreign travel is visiting historical places, scenic places and museums for the art. Living in one place, you are not on vacation all the time, you are in one place. It is not like going on a trip all the time.
If we purchased a foreign home, then maintenance would be an issue. Hiring help for that could be more difficult and expensive.
Further, I am a huge college football fan and don't want to miss the football season in the Fall.
Most of all, we would be separated from our children, grandchildren and friends.
Lastly, I would not want to be an a European country that is constantly shutting down for COVID19.