Thank you for the suggestionI know your problem with the Hibiscus. It should be nothing to do with unbalanced ports (I think). I experienced this with my 3.5mm MMCX Faaeal Hibiscus.
Try moving the cable (the braided cores itself) going out from the jack of the Hibiscus around and you should hear a very major difference.
Once you find the "right" spot, fill the gap with some glue (I used E7000).
Hope this helps.
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Edit: The Hibiscus is trashed as a "bad sounding" cable (same as yours and my past experience that sound seemed to have become hollow) in a certain FB group and I do wonder why no one has ever pointed out, noticed, or even just thought of that there might have been some defect (with an easy-to-do fix).
I tried moving the cables around near the jack, but the sound remained the same.
I will try and audition some other cables on Thursday and see if the issue remains.
thank you!