@Lupine
If you want to boot Win7 off the NVMe RAID array, it will be very difficult.
Try to check the HardwareIDs of the RAID Controller (by running Win10/11).

@kgbab:
It is very unlikely, that an AMD RAID driver will work with an Intel Chipset system.

@Lupine:
As a result of my own tests with an NVMe RAID0 array I generally do not recommend to use such configuration as system drive.
Reasons:
1. The risks are high to get a not bootable system (caused by the failure of a RAID member or just by a not properly working boot procedure).
2. You will not even recognize a performance boost while working with it (unless you are reading/writing extremely big sized files while doing tasks like video encoding).
My opinion: The very limited performance gain is not worth the risks of a not bootable system.
If you want nevertheless to create a bootable Intel RST NVMe RAID0 array, I recommend to load/integrate the Intel RST RAID driver v15.9.8.1050 WHQL.

@Lupine: Thanks for the pictures with the HardwareIDs (only the ones of the Intel SATA RAID Controller were interesting for me).
The problem is, that the DeviceID DEV_2822 is just the universal one, which is externally shown for all Intel RST SATA RAID Controllers from ICH8R up, whereas the real (specific) DeviceID is hidden.
Have you already tried the Intel RST RAID driver v15.9.8.1050 WHQL as recommended by me in post #4? It is the last Intel RST RAID driver, which definitively supports Win7 and probably your on-board Intel RAID Controller as well.