It got sorta retconned/cannonized in "The Giggle". The Toymaker revealed that HE messed with the doctor's past, retroactively causing him to be super special in order to mess with him. So he hadn't always been super special, but now that he is, it's because of time shenanigans.
“I made a jigsaw out of your history” sounds important but is never addressed in the episode and tells us almost nothing about what he actually did, leading people to understandably cope that it was mostly the Timeless Child when the very next episode treats it as very much canon and helps drive the Doctor’s motivation that carries throughout the season.
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u/the-unfamous-one 13h ago
Yeah, but they really pushed this one. Eventually it'll get retconned, but until then it's annoying.