Samsung Galaxy S21 (Plus/Ultra): How to insert the SIM card? Installation of the nano SIM cards - YouTube
MicroSD cards and your Galaxy phone or tablet
For Samsung Galaxy S21 S20 Plus Ultra Dual SIM Card Slot SD Card Tray Replace US | eBay
Samsung Galaxy S21 Ultra 5G First Look: No SD, Insane Zoom - Forbes Vetted
Amazon.com: S21 Ultra 5.0 Inch HD Display Smartphone, Support Face Recognition, Dual Card Dual Standby, 48MP Camera, 1GB RAM and 4GB ROM, 4900mAh Capacity Battery(Green)
Do the Samsung Galaxy S21, S21+ and S21 Ultra have a microSD slot? - SamMobile