Great, good for you. But what’s your point? OP explicitly said they have a specific use case for BTRFS and just wanted to know if there are any specific issues related to gaming with it. arch-chroot being slightly different with that filesystem is not an issue for 99% of EndeavourOS users.
Good to know the situation with cross compatibility has improved! I just saw enough posts of people having issues with a shared Windows/Linux NTFS drive over the years to advice against that setup.