Are self-encrypting drives really hardware-based?

I have done some research on SEDs and I'm really confused. What led me to this question was after looking up different nvme drives, I came across the SN850x, which advertises that it does not support encryption. Doing some digging I found a post that suggests it does, because it's fully OPAL compliant, but other users suggest despite this, it still doesn't support encryption. A lot of contradicting information.

Apparently there is a distinction where most SSDs will use AES …

cybersecurity doing drives encryption found hardware led opal question research support