I do this, except with Ubuntu and a btrfs volume for root.
My motherboard supports UEFI, so it doesn’t care where the EFI partition is. It’s on a USB stick.
The way I did it was by installing to a SATA SSD and then moving the EFI partition to the usb stick and then substituting the SATA SSD with the NVMe SSD using btrfs.
I think I also needed to use reEFInd temporarily to give me an UEFI shell to do some debugging.
Oh! I also setup systemd-boot so I could trivially boot the kernel directly from UEFI, stored on the EFI partition and avoided grub altogether.