Intel Virtual RAID Driver/App question on Precision 5820

Not sure if this belongs in the "Precision Fixed Workstations" forum, or in "Storage"...

I have a Precision 5820 (i9-10900x / 32 GB), and am using the on-board RAID on three 4-TB HDDs.  I have a fourth 1-TB HDD, and a couple of odd-sized NVMe drives on a PCIe adapter card.

The RAID performance is (and always has been) much slower than I THINK it should be.  I've tried to enable write caching and every other performance tweak I could, and it just seems like a dog.  I'm wondering if I should offload the whole 8 TB to individual drives, rebuild it in Windows, and let Windows manage the volume, rather than the Intel Chipset stuff, which brings me to the crux of the question.

In Device Manager, I have

"Intel(R) C600+/C220+ series chipset SATA RAID Controller", driver v7.7.0.1260 (9/30/2021)

"Intel(R) Volume Management Device NVMe RAID Controller", TWICE (both at v5.5.0/ 11/21/2018) 

On Dell's drivers and download page, is says that the "Intel Virtual RAID on CPU" driver is "designed for NVMe-based solid state drives that are connected directly to the CPU". Is that ONLY for NVMe, and it won't do me any good?

When I attempt to update the "C600+/C220+" driver from Device Manager, it says that the 2021 driver is "the best driver for this device".  Having Windows Update search for something newer doesn't lead anywhere.  Nothing else on Dell's driver page seems like a candidate, UNLESS I need the Intel CHIPSET drivers(?).

According to page 111 of the Dell Manual (chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://dl.dell.com/content/manual32840811-dell-precision-5820-tower-owner-s-manual.pdf?language=en-us), I HAVE the right driver, but I'm surprised it's not in Dell's webpage, and I can't find one at Intel.

DO I have the right driver(s) in the right version(s) for my system?