Since you disk previously was set up to boot RAID you may have to use DiskPart to clean it.
I would forget the Dell Recover <Profanity removed>. Download Win 10 install from Microsoft using the Media Creation Tool (MCT)
Allow the tool to create your USB install media. USB needs to be 8GB and not have any other files as the tool will format it.
On you Dell Support page for your Service Tag number download, all your drivers have them read to install
You would on the Same USB Thumb Drive your install is on create a Drivers Folder have all your drivers there ready to install.
Your BIOS should be Set to AHCI before you start the install
RAID ON is the normal as-shipped configuration from Dell. What storage is in the system - one SSD, one HDD, or one of each -- and in any case, what devices?