High-G/Post-Stall Maneuvers are confirmed to be in the final build half a year ago. Much of its updates are announced on the Project Wingman Discord.
Also, if you love Ace Combat 7 so much, I suggest you play all of the previous games (except Assault Horizon, Advance, Northern Wings, & Cross Rumble/Assault Horizon Legacy). Despite being the pinnacle of AC gameplay, AC7 leaves out a lot of older features that were good (massive battles in AC6, Wingman command in AC5 & Z, Wide selection of planes in AC5, etc.).
Also, AC7 has probably one of the weakest story in the series--due to its multiple change of project leads & an eventual rush in development (very evident in the Strider part of the story). Only AC6 has similar issues narratively. No doubt if Wingman sticks to its Mercenaries-type story, it'll do far better.
High-G exists only on 6 onwards, while Post-Stall exist on Assault Horizon (scripted) and 7 only.
That said, at least you can experience how AC originally plays out. Despite it feeling mechanically outdated, there are some minor details in its mechanism that AC7 purposely downgraded to entice AC7 players into fully using High-G, guided weaponry, & plane modifications.
Once you finish the PS2 trilogy, don't forget to check out the original PS1 trilogy too. Despite not having SP Weapons there, I guarantee you'll feel more sense of speed & a less Hollywood approach of storytelling in there--something we may see a return with RB-D2's Wingman.