Trump is clearly the favorite to win GA.
It’s nowhere near as "clear" as you and others are making it out to be. Regardless, even if he wins GA by 1-2%, that hardly guarantees a GOP victory in the special election (for obvious reasons).
Trump wont outperform Senate Republicans in the Sunbelt
That is likely true, but Georgia is a special case because Trump can win 48/46, but Loeffler and Perdue can't. If Trump gets a plurality win and they track him exactly, they are going to be thrown into January runoffs with likely sky high Dem turnout (assuming Trump just got reelected).
If Trump is winning GA 48/46, then the January runoffs will be featuring sky-high turnout from Republican voters because a Democratic president will have just been elected.
Trump under 50% in GA does not bode well for his reelection chances.