To be fair, Debian used to work even for FreeBSD back in the day with Debian GNU/kFreeBSD.
As both a Debian and FreeBSD person, I think I was uniquely in a position to like this, and it was awful circa 2012. Some stuff would work, and a lot of stuff didn't, because FreeBSD basic utilities weren't packaged and GNU versions didn't have full functionality: network configuration was difficult, lots of administration was also difficult. You ended up needing a FreeBSD chroot, and then you might as well use FreeBSD/FreeBSD.