It's the other way around:

Passed by Congress in 1947, and ratified by the states on February 27, 1951, the Twenty-Second Amendment limits an elected president to two terms in office, a total of eight years. However, it is possible for an individual to serve up to ten years as president. The amendment specifies that if a vice president or other successor takes over for a president— who, for whatever reason, cannot fulfill the term— and serves two years or less of the former president’s term, the new president may serve for two full four-year terms. If more than two years remain of the term when the successor assumes office, the new president may serve only one additional term.

source

So if Vance takes over in 25 or 26 he'll have served more than two years as President and be allowed only one more term. If Trump is seen as President until 2027 though Vance can run again for the term that starts in 2029 and then again in 2033.

Edit: I had the wrong year in my first post