With the model numbers most of us just look up the manual
No pics of manual pages in any case as you do not have enough posts to post such yet.
What came first, the tv with it's particular output ability or the soundbar with its input limitations?
You should still be able to utilize HDMI ARC for audio from the tv to your soundbar as both your soundbar and TV have ARC capability, not sure what you mean by you need an amp. Did you try an appropriate HDMI cable?
Perhaps the converter you got works but you haven't told the tv how to export the audio in settings? Did you try the analog connection?