Reflect definitely does support adding drivers for dissimilar hardware, in multiple ways. This is necessary because there are a lot of Reflect users in IT organizations that need to build Rescue Media that works on multiple systems.
If your XPS 13 has its SATA/NVMe mode set to RAID rather than AHCI in the BIOS, then the issue is likely that you're missing the Intel RST driver. In terms of how to add it if you're building Rescue Media from a different PC, you can manually add a driver to that PC's Rescue Media build folder under "C:\boot\macrium\[Drivers folder of whatever WinPE/RE version you're building with]\64Bit\Disk. Just create a new folder in there with any name you want, e.g. IntelRST, and copy the "F6 Floppy" version of the Intel RST drivers into that newly created folder. You can get those here
. The advantage to doing it this way is that from that point on, ALL Rescue Media created by that system will have those additional drivers baked in, which can be useful if you plan to build "multi-PC" Rescue Media on a regular basis. I have a small library of drivers that I add to Rescue Media generated by my main PC this way in order to cover hardware on other systems in my home.
But just so you know, if you're ever in a pinch and you can't rebuild Rescue Media to add drivers, then you can add drivers directly to the \Drivers folder at the root of your Rescue Media using the same method I just described above. The downside to that approach is that it only benefits that specific Rescue Media build rather than all builds you'd create going forward -- but you don't need access to Reflect to generate new Rescue Media to use this method.
Or lastly, if you're already booted into Rescue Media, you can normally go to the Restore menu and select "View Unsupported Devices", at which point you'll have an opportunity to manually supply missing drivers. But that last method might not work in the specific case of Intel RST. The reason is that Intel has kept the same PCI Device ID for the RST controller across several generations of controllers, which means that it's possible for an old RST driver to be considered a match for newer RST controllers, and therefore for Windows to load that old driver, even though the old driver won't operate properly with the new controller. So if your Rescue Media currently shows no unsupported devices, then it's probably because Windows loaded an Intel RST driver that it had built into its kernel. At that point, there wouldn't appear to be any "unsupported" devices, which means you wouldn't be able to load a driver through the interface I'm talking about, but of course your storage still isn't visible because that old driver isn't a USABLE match. This behavior is not typical for hardware; Intel is operating unusually with their RST controller. But if that's your predicament, then putting an Intel RST driver into the Drivers folder of your Rescue Media, either directly onto your Rescue Media or into the build folder so that it gets put there during a Rescue Media build, should resolve the issue because Reflect will load that newer driver at launch when it sees it in that folder.