I have switched between XFV and XFE on an XFA handset (bought from Samsung directly), multiple times, using the default Odin method.
Provided the correct CSC file was flashed (resulting in a full factory reset), I have not had issues. CSC has always played along, except for the third indicator in Settings-About Phone-Software Information-Service provider SW ver, which is fixed to the CSC the handset originally came with.
No VoLTE on XFE, but I have not missed it, and OTAs have been more regular than XFV. I always download and flash a full factory firmware set to update before the OTA is out anyway.
XFE is also unbranded and can be updated with any of the European firmware packs for the OXM region.
I am currently running this one:
https://www.sammobile.com/firmwares/galaxy-note8/SM-N950F/XEF/download/N950FXXU3BRA8/205807/
It initially sets the CSC as XEF (France), but asks to do a reset on first boot (In French), after which it settles on XFE. Make sure that you have your SIM card in the handset on that first boot, else it will stay on XEF!
Note that Sammobile reckons flashing via Odin invalidates your warranty, so do this at your own risk.
CSC Regions:
https://www.sammobile.com/forum/showthread.php?t=39186