Nah AGT and Picard don’t happen in the same timeline. AGT was some sort of alternate timeline. But the events of the Prime timeline diverge enough from the AGT timeline that it makes more sense that the new warp scale was unique to the AGT timeline and didn’t happen in the Prime.
The scale changed from TOS to TNG. Then in All Good Things which is the only other time we’ve seen it presumably they changed the scale again.
And then back for Picard when the max sustainable is warp 9.99.
Nah AGT and Picard don’t happen in the same timeline. AGT was some sort of alternate timeline. But the events of the Prime timeline diverge enough from the AGT timeline that it makes more sense that the new warp scale was unique to the AGT timeline and didn’t happen in the Prime.