Assuming it's a narrow victory royale, yes. Trump as a whole has repeadtedly put the GA GOP in a bind that likely cost them the runoffs and his poor performance in Atlanta caused him to lose the state.
Northern Georgia is probably the most "Trumpy" part of the state that nets the most votes for the GOP given it's relatively dense nature, so GOP turnout there will be key.
No, it would be pure demographic change. Stacey Abrams is the most overhyped Dem candidate ever. She just happened to be in the right place at (nearly) the right time.
I disagree it would be "pure demographic change". Demographic shifts in GA def help, but between 2016 and 2020 Pres, the voter turnout increase in much of greater Atlanta was absolutely massive and above just grwoth and above the national increase. The voter activation efforts definitely had an impact though how big is hard to truly say.
I don't think Abrams herself is the strongest candidate in terms of actually flipping voters, but her efforts have definitely turned-out voters which I'd argue is ultimately more important.
In hindsight, her 2018 loss wasn't particuarly impressive given statewide Dem wins since then but it was part of a greater pretty linear shift in Dems favour.