I think Fichte did take it further than Kant by arguing that we can regard the moral law as objectively valid only by seeing it as addressed to us by another being, even though Fichte thought God could not literally be a person who could address us.
Every song falls short of the glory of what a song could be. That's why the urge is there to start again and yet again. Often it's the fault of rhyme. I've discovered a hundred times that there just aren't enough rhymes to say what I wanted to say, so I said something else instead. Sometimes it was a better thing, but the thing I meant to say went unsaid. So there's an opening for another song.