Even after the end of Steven Universe: Future, people still wonder if Steven and the Stevens secretly had a dark ending. There were a lot of Stevens that disappeared when the Glass of Time was destroyed, and we know Steven is pretty crucial to Earth’s safety in the main Steven Universe timeline. If there were any timelines missing their Steven, they’d be a lot less happy.
Thankfully, Steven Universe’s flirtation with time travel has a happy ending: Stevens weren’t snatched from alternate timelines in Steven and the Stevens, they were created with magical sand. This is why the Diamonds never tried to use the Glass of Time to save Pink from being shattered: it can only create a new past, never alter the real one.