I have had some compatibility issues with ExFat and hard drives. It’s really a format originally intended for thumb drives. Native Windows NT can be read on Macs, but not written without extra software – either Tuxera or Paragon. I personally use Tuxera to write Windows NT formatted drives and it has always worked well. It installs as an OS extension and once installed, the option shows up in the Disk Utility pulldown menu.
One thing I’ve run into with the “free” versions is that they are locked to that brand of drive. If you later try to use it to format a different brand of drive (even if it’s the same parent company), it may not work.