hello terry8uwg2,
to clarify,
fused keys can no longer be read once the ODM production mode bit is burned; the only exception is the Reserved_ODM fuses; Reserved_ODM will be disabled after you’d program the ODM_lock fuse bit.
it’s Secureboot is to prevent execution of unauthorized code during boot process through chain-of-trust.
so,
you may have your use-case to store keys in fuse for using before program the ODM_lock.