Been through Atlanta many times over the years. The traffic is legendary. We often don't have a good alternate route. My experience has been the best route has usually been right through the center, rather than the east or west bypass. I've heard that from others who pass through Atlanta often. Check the Waze app before you reach the bypass choice.
If you can plan your trip, the very best day is Sunday. Saturday is better than weekdays. Midday any day is better than morning and afternoon rush times. Earlier this year we went through on a holiday Monday and although still busy, it wasn't bad at all.
I-77 to I-75 may be an option, but the mountains between Beckley, WV and Fancy Gap, VA can be problematic. We had to wait out the fog one morning. Cars don't seem to slow for rainy or wet mountain highways.
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