Why did Ossoff underperform Biden in November?

[OneJ]

A few reasons I can think of:

1. Ossoff, like plenty of other Democratic candidates across the country, just wasn't strong enough on his own to outperform the top of the ticket.

2. Perdue was the incumbent who's relatively competent and not particularly unpopular.

3. Trump being a particularly bad to a large enough amount of voters that it was difficult to outperform Biden anyway which sort of goes back to point 1.