I’ve read numerous accounts of her promoting Biden in her current concerts. You can choose to believe that or not.
Everything Taylor Swift says on stage is filmed by countless cell phones and posted on-line. I haven't seen any evidence that she promotes Biden during her concerts.
Now, she publicly endorsed Biden in 2020 and publicly celebrated his win following the election. This is true. And she will likely endorse him again.
Biden returned the favor last Thanksgiving when he pardoned the turkey by mixing Swift with Britney Spears in typical Biden dementia.