Hello,
All i.MX8 have been validate to work with PCIe, we have not tested the LTE for 4G but check the errata of this WinIoT version, Limitation: PCIe DMA supports 32-bit addressing only.
Connected PCIe devices using memory > 4 GB may work
incorrectly. Workaround: Allocate memory for PCIe devices
below 4G or copy data to lower address space in the device
driver. More information:
https://www.nxp.com/docs/en/release-note/IMXWNR.pdf
Regards