Why does my C: drive not have an EFI partition?

As Ghot said, you have no efi on the new disk because you did not disconnect the other drive when you clean installed onto this drive. Your issue is not JUST that there is no efi partition on the new drive, but that all boot configuration data for both OSes is written to the old drive.

Regarding optane, you see “Task Manager shows that both my SSDs and HDD are in RAID” because both Optane and RAID are enabled in bios. Intel Optane was a failed endeavor by Intel that is a can of worms.

I dealt with both Optane and RAID in mine quite easily during a clean install. While both can be done in a live system, I would never take responsibility for advising anyone to do it or how to do it without data loss. The following article deals ONLY WITH OPTANE. Disabling RAID in a live system is an entirely separate procedure. You can choose for yourself. Maybe this Intel article will help. Use at your own risk.

Backup your data!!!!