Samsung Electronics GmbH
Hello,
the Galaxy S21 Ultra supports 25W fast charging and is compatible with the Powerbank EB-P4520.
Best regards from Eschborn
Your Samsung Service Team

Yes, you can charge the Samsung S21 Ultra with Fast Charging via the power bank. The S21 Ultra supports up to 25 W Super Fast Charging, and the power bank offers Power Delivery with up to 45 W, which is compatible and enables fast charging. However, the S21 Ultra charges with a maximum of 25 W, even if the power bank can deliver more power.