Final Cut is just the Director’s Cut with more polish.

The DC was made from Scott’s notes without his direct involvement. So when they took out the narration, that’s all they did - they didn’t alter the editing to match the fact that there’s now no one talking in the background. The added unicorn dream was also a little haphazardly done.

For the Final Cut, Scott was directly involved, so the editing was tightened during parts where narration was removed (mostly done to match the work print), and the unicorn dream was integrated better. Then Scott decided to fix some other things, like lip sync in one scene, replacing a stunt double’s head with the actual actor in one scene, changing a couple backgrounds for continuity, and a few other little effects fixes.

So yeah, the FC is overall the best version, but it isn’t that different from the DC.

If you want to watch it sooner without waiting, I’d say go ahead and watch the DC.