Statistically speaking and based on findings from House races, it’s a sound strategic move:

If winning more seats is the top priority, the preponderance of evidence suggests that nominating moderate, centrist candidates in districts where Republicans have a chance of winning is the more effective strategy, with the caveat that a contemporary moderate is substantially more liberal than the moderate of two decades ago.

Most — though by no means all — scholarly work supports the view that moderate candidates in competitive districts are more likely to win.

It also might be part of the reason he won in 2020:

The data [from Pew] suggests that the progressive vision of winning a presidential election simply by mobilizing strong support from Democratic constituencies simply did not materialize for Mr. Biden. While many Democrats had hoped to overwhelm Mr. Trump with a surge in turnout among young and nonwhite voters, the new data confirms that neither candidate claimed a decisive advantage in the highest turnout election since 1900.

Instead, Mr. Trump enjoyed a turnout advantage fairly similar to his edge in 2016, when many Democrats blamed Hillary Clinton’s defeat on a failure to mobilize young and nonwhite voters. If anything, Mr. Trump enjoyed an even larger turnout edge while Mr. Biden lost ground among nearly every Democratic base constituency. Only his gains among moderate to conservative voting groups allowed him to prevail.