My requirements:

• No visible Screws
• No glueing
• Diffusor should separate the pixels very well, an should have very thin walls
• Diffusor shoud have a light color on the top to be inconspicuous
• Face of the front should be nice looking

Especially the frame needs needs some support.

You will need a printer with 240mm in X or Y direction for the middle part of the frame. If you have a smaller printer you have to split the part in the middle and glue it together.

I used  a PET foil with a thickness of 0,4mm which I had used for bult faceshields during the corona pandamic. And for the diffusion layer I used 4 sheets of 0,075 thick diffusor films from amazon.
Diffusionsgel-Filter, 6 Packungen, 40 x 50 cm, Beleuchtungs-Diffusor-Film, Rolle, Fotografie, Video für LED-Blitzlicht, Stroboskoplicht: Amazon.de: Elektronik & Foto

As screws I used M4 (8x6mm and 4x16mm) together with the cheap threaded inserts with 5,4mm height. I inserted them with my soldering iron and the tool from CNC-Kitchen: [https://www.printables.com/de/model/167924-case-for-cnc-kitchen-threaded-inserts-soldering-ti](https://www.printables.com/de/model/167924-case-for-cnc-kitchen-threaded-inserts-soldering-ti) 
It's a huge difference to use these tools compared with the standard soldering iron tips.

I use the display together with home assistant and the project: [https://github.com/lubeda/EspHoMaTriXv2](https://github.com/lubeda/EspHoMaTriXv2)