The suggestions I have seen for fixing this involve running mongo on the command line, but the mongo command line was removed in v6.x, and the new MongoSH or Compass tools do not seem to have support for FreeBSD yet.
Any ideas how I can get this back up? How can I update the feature compatibility?
I don’t know if you could now run mongo from the command line, but I used the version from Node (see mongosh - npm)
Now you can use the instructions from the MongoDB upgrade page I linked to above to see what your current upgrade compatibility is and change it to 5.0.