The Craig era was the Time Lords trying to brainwash Blofeld into being good by wiping both his and Bond's memories, regenerating them as children (a la "The Timeless Children"), and making them brothers.
The reason Blofeld doesn't recognize Bond in OHMSS is because he's newly regenerated.
And under this theory, OHMSS would take place after Diamonds Are Forever, which would fix the problem of that movie pretending its predecessor doesn't exist.
Aside from two of the best theme songs in the series, you ain't missing much unless you're really into camp Bond, but DAF does have Charles "it's just a jump to the left..." Gray as Blofeld.
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The reason Blofeld doesn't recognize Bond in OHMSS is because he's newly regenerated.
And under this theory, OHMSS would take place after Diamonds Are Forever, which would fix the problem of that movie pretending its predecessor doesn't exist.