Well, if you read the Help topic about the Game Explorer, it says that it only indexes games of 5 0 and above.
https://support.chess.com/article/368-what-is-the-game-explorer
Currently, the Explorer does not index Live Chess games shorter than 5 | 0, Chess960 games, or any games of fewer than four moves in length.
So the bullet games will never load. And you undoubtedly have a few games or 3 moves or fewer.
So that gives you 1,314 games out of about 1,514?
/ I don't see how leaving it sitting on the Game Explorer page could possibly make a difference. I think that they were suggesting it performs an update on the index when you request the page. Whether you leave it sitting on the page or turn off your device would make no difference.
So for a couple months now, I've been starting to use the Game Explorer more in depth to see what openings/variations i am having a worse win % on and to go ahead and fix my play. However, in opening explorer i have a total of around 1200-1300 games to view from, yet I have played over 1400 blitz games, 500 bullet games, and around 50 rapid. I contacted support and they told me to leave it on the explorer to allow games to update, however there is no games updating from March 9th onwards, this also was happening to me a few months ago, however it did update when i was just sitting in the explorer months ago. I've now left it in the explorer for over 3 nights now, and yet no more games have been added, hope there is a fix or atleast other people are experiencing the same thing.