This Is Where I'd Put My Trophy If I Had One

They'll vote for Biden. Biden won the election. He's the President Elect.

Nobody is the president elect until they vote

We vote. The electors are pledged to our vote. And we voted a month ago. Biden won the election. So he's the President Elect.

From Wiki:

According to legal experts, use of the title "president-elect" is often informal, indicating the candidate projected to win in the electoral college vote. However, the candidate does not officially become the president-elect until "after the General Services Administration initiates the transfer of power by 'ascertaining' the election results and Congress officially counts the electoral votes on Jan. 6."[10]

Right, so do you see how that first sentence you copy and pasted explains that it is the correct term to use in all but the most ceremonial of technicalities?