The rest of what you wrote is discredited by the first two sentences of the second paragraph.
Hardly. It's quite possible to make a mostly safe 12D-2R gerrymander on 2020 presidential data.
10 years of trends later, t
hinking the Democrats would leave the Republicans with more than five seats seems fairly absurd.
If this is indeed the case (and I question that it is), the GOP should either gerrymander the state legislature to keep a lock on it for at least a decade more, to ensure Democrats can never activate such a map, or they should call for a switch to an independent commission just after the maps for the 2020s are decided. That way the maps would always be fair and if Democrats eventually did come into power, they'd have to either deal with fair maps or abandon their anti-gerrymandering principles to repeal the independent commission (if even possible, which it might not be).
Here’s a link to a 12-2 gerrymander on 2020 presidential data. Somewhat convoluted but this is obviously the most extreme scenario– if you’re giving the Republicans 4 or 5 seats it’s incredibly simple.
https://talkelections.org/FORUM/index.php?topic=346841.msg8274240#msg8274240
As for gerrymandering the state legislature- Georgia isn’t Wisconsin. If the northern suburbs continue to go left, there isn’t any feasible way for the Republicans to hang onto the state legislature once the Dems start winning the PV by more than a few points.
Don't know definitively, but I suspect it's possible to do so by diluting suburban votes by surrounding them by safely Republican rural ones. For example, a district might be 60-40% rural, and even if it trends leftward, it will remain Republican.
If you don't know definitively, then it's probably best to avoid arguing with someone who does know what he's talking about. What you're describing here is a pack and crack, which is the basic principle of gerrymandering. I would imagine that every single poster on this board is familiar with it. The issue here and the argument being made is that this will be difficult to accomplish for Republicans in Georgia, because so many of the state's Democratic voters are in the Atlanta metropolitan area and because the periphery of the metropolitan area is swinging Democratic faster than anywhere else in the country.