Trump has never wanted to govern, and ran in 2016 only to feed his ego.
Not sure anything has changed. Trump can win primaries, but not a General Election. The biggest reason Trump would not run is fear of losing.
In contrast, Formidable GOP General Election candidates (e.g. Larry Hogan) cannot win GOP primaries, because the base only wants candidates who spew disinformation.
Biden never intended to serve two terms. He simply cannot say so, this early in his Presidency. That will change in Spring/Summer 2023.
The Democrats will need a force of nature in 2024 to draw turnout plus draw swing voters.
Link: https://www.washingtonpost.com/politics/2022/01/29/sundaytake-trump-polls/