@waytogo
As long as Gigabyte hasn’t given your mainboard a BIOS with natively complete NVMe support, you will not see the model name of your NVMe SSD within the BIOS. Nevertheless you can use it as bootable system drive, if you follow my advices within the chapter “Step 4 - Installation of Win10/11 onto the NVMe SSD”, which is within >this< Guide.
No, you don’t need the SATA SSD and can even completely remove it, but nevertheless will be able to boot off the NVMe SSD. The only thing you have to do is to create an EFI boot partition on it according to my Guide.