I wouldn't think too much about it too. DC will change plans and directions several times before we get there.
I've never been a fan of people saying "Batman Beyond is the definitive future for Batman" or "Batman Annual #2 is the canon future". They're not. It doesn't matter what the writers or DC say, that's just not how comics work.
And to come back to King's run: Wasn't Gotham Girl supposed to marry Duke and wasn't Bruce supposed to die or something? It's been too long, but there was something and nothing came of it.
Always take statements about DC events that are set in the future with a grain of salt.
The only reason I posted the picture was because some people apparently only heard about it, but didn't read Doomsday Clock 12 and believed it confirmed Selina giving birth to Helena Wayne.
It states that in 2026 Bruce has a lost daughter and Clark is looking for her, because they need her help to save Bruce's son. It doesn't even confirm that it's about Damian, even though DC is usually talking about Damian when the phrase a sentence like that.
I think it's pretty obvious why a six year old Helena Wayne doesn't fit here. She would need to be aged up in some way. Other problems that arise from this have already been discussed by you guys.
It could be Helena Wayne from Earth 2 (fits better with the "lost" part and doesn't involve awkward age ups).
Even bringing Athanasia Al Ghul into main continuity is a possibility, nothing in this says it's about Selina's daughter.
There are a lot of ways this could play out. It doesn't confirm anything.