There are differences with Batman.
For example:
What color is Jason Todd's hair? How did Batman meet him?
What did Catwoman do before becoming Catwoman? Prostitute? Thief? Mafia princess? Airline stewardess?
Who came first: Dick Grayson as Robin or the Joker?
When did Bruce Wayne meet Alfred?
The ultimate thing here is: you can blend these details. You can say Catwoman was a prostitute to pay the bills while working on an airline and stealing jewels and that she's a Falcone cousin. They don't have to contradict. And many of the details don't matter for the purposes of telling a Batman story. And if two writers wanted to reference contradictory events, the result is not a timeline change. It's just a shrug of the shoulders from editors.
With Superman, the detail changes matter more. honestly, they matter the least with Krypton aside from how Jor-El dressed and styled his hair. Because there's nothing inherently contradicting the idea that they were Xenophobic and genetically blocked from space travel generally, that Mon-El visited there, that Zod was a general, that Argo City somehow survived, or that they used computers that look like crystals called "sunstone". They can pretty much all be true if you squint.
Now, the Kents have to be alive or dead when Superman left Smallville. Either he was Superboy or wasn't. Either he has a dog named Krypto or doesn't. Either Luthor went to school with Perry White or he met Clark in Smallville. That said, you could totally fudge a lot of this stuff with new options (ie. maybe everyone forgot Superboy or the Kents got sick but didn't die or died and came back, maybe Lex was a time traveler as a young man or had a son who was friends with Clark in Smallville and died). But that creates a third option.