100% agree with the wizard! Black LED acrylic looks amazing with approximately 18-23mm spacing from LEDs to panel. Diffusion is perfect and very high contrast compared to white diffuser materials. Completely eliminates retina-searing pixels with a minimal loss of brightness. It’s the only diffuser I’ve found that works with a single layer.
If you are seeing individual LEDs, try increasing the distance to the panel. It is also possible you don’t have the exact same black LED acrylic panel that we used for our displays.
Here is a link to view a demonstration of Black LED Acrylic diffusion.
8x8 SK9822 Matrix Through Black LED Acrylic at 17mm
And a link to the manufacturer. (Opti-K by Chemcast)
https://www.chemcast.com.mx/optik.html
And a link to a distributor. (TAP Plastics)
https://www.tapplastics.com/product/plastics/cut_to_size_plastic/black_led_sheet/668