I see.  Your Intel RST has been re-installed and so was your operating system. You can use diskpart to create a small partition on intended boot drive, then use bcdboot command to install EFI boot file.  But I don't know if this machine may have any other hidden issue due to omission info (not intentionally).  My suggestion is, starting from scratch, installing all the drives you want, re-adjust BIOS settings to match your hardware settings.  Then performing a clean Windows installation directly to the new NVMe drive (opportunity to try Win 11) without any of Dell apps or tools.  You spent 2 days to find the issues, you can spend 2 hours and your machine will work better than new.   For software, a clean install will give you the best performance and in a way, forcing you to have the latest apps, drivers, etc...without all the patches, broken registries, hidden issues.   For hardware, the XPS 8930 was known for lack of cooling.  You can upgrade top case fan to a 120 mm, adding a couple fans to the front existing mounts.  They will definitely help with thermal improvements.  The bottom PCIe slot is a x4, which can accommodate an M.2 adapter for storage expansion if you are interested.  
I have a XPS 8390 desktop which came with a m.2 256G drive that has the windows 10 OS on it. Several years ago I installed a Samsung SSD and put a fresh copy of windows 10 on the SSD, left the original m.2 OS drive intact. It shows up in Win10 as a data drive (I don't remember whether I did anything to have the PC boot from my freshly installed Win10 instead of the pre-installed one). But I remember I did not do any migration. Now I am trying to replace the 256G M.2 drive with a new 2TB one and found out I can't boot from SSD or anywhere if I have the original M.2 drive removed. I can put the new m.2 drive in and it shows up in BIOS. But the PC won't boot Dose DELL PC look for the original OS installation drive during boot-up? If so, how do I get around it to replace the original m.2 drive with a new one?   Thanks
XPS 8930 Failed to replace the m.2 drive