To not release a single accompanying the White Album was probably the worst single-related mistake of the Beatles ever
Simply because they didn't release a single since August, so was a good time to release a new song to the radios at November. Consider that their next single wasn't released until April/May 1969 (Get Back), so it was an 8-month gap between the two singles! Quite a mistake! They had the perfect space to release another single between them, and for sure it would be a song from the White Album...
...Or not!? Because they could extract 2 songs from the album, leaving it with "only" 28 songs,
releasing the two songs as only-single songs. I suppose a good option could be Ob-La-Di, Ob-La-Da / Savoy Truffle. A sure #1 hit!