AW3225QF, HDMI, problem with Dolby/Atmos 120Hz

Hello?

First of all, I'm not familiar with English. Please take this into consideration and read it.

I have a problem with my AW3225QF.

No. 1 HDMI port (eARC) = DENON (WITH bundle cable)
No. 2 HDMI port = RTX4090 (High SPEED 2.1 HDMI cable)

AW3225QF is connected as above. The firmware has been updated.

Problem 1.
Monitor frequency cannot be changed to 240HZ. Only 120HZ can be set.
Both Windows/NDIVA cannot be changed more than 120.

Problem 2.
When eARC is used, the DOLBY ATMOS home theater is not enabled in the window, only the headphone mode is enabled.


These problems cannot be solved by removing AVR and just connecting the monitor.

My previous 2.1 HDMI cable didn't solve it.

I bought an additional 2.1 cable with 4K240HZ support from Amazon, but it didn't solve it.

Does anyone know a solution?
I think the product is defective. I'm wondering if I should get a refund.

My existing system consists of an LG 42C2 TV and a DENON AVR X2500 home theater. This system used eARC and Dolby Atmos home theater mode worked fine on my computer.