Yes - this will accept and passthrough HDR signals fine. My issues were just bad cabling in my setup.
The grabbed image is not tone-mapped, so will be washed out (which is normal for almost all affordable grabbers).
What I can’t advise on is how this will behave without a display connected to it’s output. Mine is connected between my amplifier and TV.
Hey, I bought the same grabber, but it's not giving HDR to my LG TV - the input is an Apple TV 4K. How is yours set up?