The typo for the section 2.2.3, the first command of quartus_pfg -c -o, the "-" is wrong.
User Guide: Agilex™ 7 Device Security User Guide
ID: 683823
Version: 7/07/2023
Section: 2.2.3. Signing Configuration Bitstream Using the quartus_sign Command
2.2.3. Signing Configuration Bitstream Using the quartus_sign Command
Wrong information: quartus_pfg –c –o fw_source=signed_agilex.zip -o sign_later=ON \ design.sof unsigned_bitstream.rbf
Correct information should be like: quartus_pfg -c -o fw_source=signed_agilex.zip -o sign_later=ON \ design.sof unsigned_bitstream.rbf