It’s not reading into, it’s just taking the manga at face value.
Acknowledging mysteries and unanswered questions isn't taking them at face value, it's pointing out the obvious the author has long term. consequential plans for those answers.
Blackbeard's connection to Rocks isn't even acknowledged in the story.
Sabo was shown as this generations oden and wants to write a book of his adventures like odens journal.
Making this much out of a book is a prime example of reading too much into things, especially when you have Yamato RIGHT THERE as the character loudly labeling themselves Oden.
Sabo has no connection to Oden any more than he does Nami.
Logically, that means Sabo will ultimately join the SHP like Oden the Roger pirates.
There is no logic supporting Sabo abandoning his value systems and his work on liberating people.
What would ever make you think Sabo is not a true believer in the mission of Revolutionaries?
Blackbeard was told specifically he’s not the one to shoulder the 800 years of history connected to being a D which we know are the enemies of Imu. So Blackbeard won’t outlast Imu.
Blackbeard was told he's not the one Roger was waiting on.
We later learned Roger learned of Joyboy and lamented not being born in the right era, meaning the person he was waiting for was probably Joyboy, i.e. Luffy.
Later on, we learned from Vegapunk there is some kind of traitor among the D clan.
I mean, come on dude, put yourself in the boots of a writer. It's so clear Oda is working towards Blackbeard succeeding at least where Rocks failed, which is usurping Imu.