[wizziwig]

But without a Debug Log - it's hard to help. I might have a reason to plug mine in after amazon made great firmware fucking the last week

This is absolutely true!!! My question was just theoretical yet, to make myself sure that my result is just my problem or a general one. If a general one I will leave it itself. If seems that is only my problem then I will start to debug it!

You are definitely not alone.  Another user reported the same thing where 4K SDR worked fine and 4K HDR didn't.  Check this post and their earlier comments in the thread.  Presuming 4K HDR works in other streaming apps, I'm guessing some sort of compatibility issue.  Please send fritsch your debug logs.