There are at least two solutions:
1. Deploy your own Secure Boot keys and protect them with a firmware password whatever mechanism your particular system has to lock down Secure Boot settings.
2. Use TPM-based security so that even knowing the passphrase doesn’t unlock FDE unless the PCRs are correct.
#1 is a bit of a pain. #2 is a huge pain because getting PCR rules right is somewhere between miserable and impossible, especially if you don’t want to accidentally lock yourself out when you update firmware or your OS image.
Of course, people break PCR-based security on a somewhat regular basis, so maybe you want #1 and #2.