How to Change SATA Mode from RAID to AHCI on OMEN 15 Notebook?

[LitWorx]

Problem: I can't change HDD SATA mode from RAID to AHCI because the BIOS does not provide an option to do so in HP OMEN 15-dc0010nr Notebook.
Background: I purchased this HP OMEN 15 notebook over a year ago and it came with a 128GB SSD and a 1TB HDD. The SSD is set to NVMe device type and the HDD is set to RAID device type. I am unsure whether the HDD was initially set to RAID SATA mode or whether that was the result of my tinkering with the preinstalled Intel RST (Rapid Storage Technology). I was upgrading to a new 1TB SSD and was going to perform a clean install of Windows 10 Pro. As part of the upgrade I was going to change the HDD to AHCI as RAID would not be used and I was never able to make the SSD disk caching for the HDD work on Intel RST. My BIOS is updated to the HP's latest version (AMI F.12 April 2020).

After extensive research on changing the SATA mode from RAID to AHCI, I found that there were two options for pre-install Windows and two options for post-install Windows.
Option 1: Before Windows Install. All sources directed to change the SATA mode from RAID to AHCI in the BIOS before the operating system install. This was impossible as there is not an option in the BIOS to change the SATA mode.
Option 2: During Windows Install. Sources referenced changing the SATA mode during the Windows installation. This could not be performed as I was unable to find this option. As an aside, this seemed to be mute as I was installing Windows on the SSD (NVMe) not the HDD (SATA).

I needed to proceed with installing the 1TB SSD so that I could use the original 128GB SSD in a new computer that had to be up and running ASAP. As such, I proceeded with the SSD upgrade and installed Windows 10 Pro on the new 1TB SSD. After the upgrade and Windows clean install, the HDD was still in the RAID SATA mode and there was not an option to change that in BIOS. I had found that if Windows was installed while the secondary HDD was still in RAID mode that Windows may not enable the AHCI drivers.

Diving deeper, I found that the AHCI driver (storahci.sys Microsoft Standard SATA AHCI Driver) was indeed present in the Windows system folder with the following settings:
⦁ Started: No
⦁ Start Mode: Manual
⦁ State: Stopped
⦁ Status: OK
⦁ Error Control: Critical
⦁ Accept Pause: No
⦁ Accept Stop: No

The active driver is the iastorac.sys Intel Chipset SATA/PCIe RST Premium Controller driver [possibly accompanied by some other Intel drivers which I will not involve here] with the following settings:
⦁ Started: Yes
⦁ Start Mode: Boot
⦁ State: Running
⦁ Status: OK
⦁ Error Control: Normal
⦁ Accept Pause: No
⦁ Accept Stop: Yes

Which leads me to the two Windows post-intall options to change the SATA mode from RAID to AHCI.
Option 3: Safeboot Method. Several sources- including an HP forum- detailed using Safeboot. The problem- this still required going to the BIOS to change SATA from RAID to AHCI. As the BIOS does not give me that option, this was a non-starter.
Option 4: RegEdit Method. A handful of sources detailed a way of going into the Registry Editor to reset the Intle RST driver(s) and the AHCI driver and then upon restart the AHCI driver would be enabled. After careful study of several of these procedures accompanied by close examination of all relevant drivers located within my System Folder, I arrived at three possible variations of this method that may have to be tried. Before embarking on such an adventurous quest, I decided to turn to HP and HP Community to ascertain whether there was a simpler (and safer) means to merely change my SATA mode from RAID to AHCI.

Question 1: Why isn't there a BIOS option to change the SATA mode on the HP OMEN 15-dc0010nr notebook? If HP has done this intentionally, it would appear ill-advised to prevent customers from managing such basic computer functionality.
Question 2: Is there a way to enable the ability to change the SATA mode within the BIOS?
Question 3: If there is not an option to change SATA mode within BIOS, is/are there any recommeded workaround(s)?