It turns out that Macrium Reflect cannot create a USB drive that boots into Windows either. In fact it says on their documentation page "Windows cannot boot from a USB-connected drive. This is a restriction imposed by Windows. If you clone your system disk to a USB-connected external drive then, to boot your clone,  the physical disk must be removed from the USB caddy and attached internally." So it seems my only option remaining to repair this drive with a utility that runs under Windows is to remove the drive from the laptop, and hook it up as an external drive to a working laptop via a NVME-to-USB adapter.
I've been browsing other similar threads and they have not helped. The Optane accelerator in my Inspiron 7590 2-in-1 had a high CPI load, so I followed Intel's instructions to update it. At the end of step 2, I rebooted and found that the file system is now in RAW mode. The automatic repair utility that runs cannot repair it. Diskpart showed it still has an allocated volume, presumably with my precious data on it. The AOMEI partition assistant actually can actually repair this without reformatting, but to do that, I need to boot into a Windows environment from USB so I can run that program. So I created a "Windows To Go" USB drive, but I cannot figure out how to get it to boot. There is no .efi file on the drive in the root or the \boot directory. There is a bootmgr.efi file in \Windows\Boot\EFI, but no matter where I point the BIOS in "add boot option", even after removing the internal drive from the list, when I try to boot from the USB the Dell Support Assistent opens into a self-test, when that's done I get a screen saying "Error: NO_BOOT". Short of opening up the laptop to removing the drive putting an NVME-to-USB adapter on it to treat it as an external drive on a working laptop, what should I to boot into a Windows environment?
Internal drive in RAW, need to know how to boot "Windows To Go" USB