Did you even bother to read the article you linked to, and posted a portion thereaponof?
"...the president-elect could run for a third term in 2028,..."
The author is speculating about the time between the 2028 election and the end of January 2029 when Vance will be sworn in, meaning Trump will be ticking box #2 following Vance's landslide victory.
He in no way says or implies that Trump will be a lame duck throughout his entire second maganificent term.