Skipping a lot of pitfalls by assuming like for like standard of living, family stays together, similar job, and no question whether we’d get in or not, probably one of the scandiavian countries. I’d need to do some research, but there’s one of them (or more?) I thought that had both super high taxes (wait for it) and also a super happy population with a wide array of well thought out public services.

I’d settle for any country where I could be reasonably likely not to encounter death camps or civil war within the next few decades, though.