not detect had drive in bios

dear sir,

We have dell 7820 workstation , when doing reinstallation of rhel 8.7 we are not able to see hdd
to load os ,we checked in bios also but not found ,we clear raid configuration and tried raid 0,1
but in raid controllers m2.ssds are displaying but in bios not identified we tried changing sata settings
ahci,raid on,disable modes also but not showing storage drives in boot sequence .when check
dell preboot diagnostics test passed and shows no boot device found

please provide solution

THANKS & REGARDS

CH.MALLESH