iMac 27" 2017 Fusion drive only appears as HDD

I bought a 2017 5k iMac. It has a 1 TB FusionDrive, but the system only recognizes it as a plain HDD. I already tried to delete it in the disk manager, I reinstalled Monterey, but nothing changed. I tried several things in the Terminal, but nothing works, diskutil resetFusion, diskutil cs delete "Macintosh HD", etc. I will listen to any solution. Thanks in advance.