As a Trump supporter, he doesn't have to pretend to have won the election. In fact, I'm concerned that his temper tantrum might hurt in the Georgia races, even if I think Loeffler and Perdue ultimately pull them out.
Before I saw he wasn't going to concede and instead was going to do all these legal challenges, I would've said the GA runoffs favored Republicans. Now, and directly because of Trump and the GOP acting like sore losers, I think both races are tilt Democrat. The Loeffler/Warnock race especially is tilt Democratic now.