This is one of Vox's Future Perfect predictions for 2023; they give it a 75% chance:

Every year, the World Happiness Report ranks countries in terms of the happiness of their populations. It’s an attempt to pay more attention to indicators of subjective well-being as opposed to raw GDP.

Finland has been the happiest country for five years running, thanks to its well-run public services, high levels of trust in authority, and low levels of crime and inequality, among other things. And in 2022, researchers noted that its victory wasn’t even a close call: Its score was “significantly ahead” of every other country. So I think it’s likely to hold onto the top spot in 2023. As for America, its ranking did improve recently — from 19th place in 2021 to 16th place in 2022 — but it has never made it into the top dozen spots.

(Vox)

Resolves according to Vox Future Perfect's judgment at the end of the year.