SUPCASE UB Pro Series Case for Samsung Galaxy S21 Ultra 5G(2021 Release) Without Built-in Screen Protector, Full-Body Dual Layer Rugged Holster & Kickstand Case With S Pen Slot (Black) https://www.amazon.com/dp/B0989N3WZC/ref=cm_sw_r_apan_glt_fabc_JYJQK52T5P7GY0YDFE6T?_encoding=UTF8&psc=1

I wish I could find a good rugged case that has an S-Pen slot.

Edit [SUPCASE went and made a updated version of the Unicorn Beetle Pro and added a S-Pen slot. ](SUPCASE Unicorn Beetle Pro Series Case for Samsung Galaxy S21 Ultra 5G (2021 Release), Full-Body Dual Layer Rugged Holster & Kickstand Case with S Pen Slot (Black) https://www.amazon.com/dp/B0989N3WZC/ref=cm_sw_r_apan_glt_fabc_QEGTC9K72SAH6HVKVYRE)