Problem with Target Texture

Hi,
My purpose is to make a material that I can put on any object and I'll render for everyone in the scene some text that will change throughout.

So I tried creating a Render Texture, then I created a new camera and selected the already created Render Texture as the output from the camera. Then I created a Canvas that only renders for the Camera that has output as a Render Texture. And last thing, I put that Render Texture as the base for the material that I applied to the cube.

The problem here is that for me as locally everything works as it should, when I change the text via code it shows up and renders on that said cube, but for the other person or the other build of the game only the environment changes what the camera sees except the text.

I might also mention that I use Photon PUN2. Below I attach some pictures for explanation.

https://ctrlv.cz/YvTt
https://ctrlv.cz/YdEm (Here it works how it should for all of them, but when I change text and position just for that who change it works.)
.

https://ctrlv.cz/uEcy

https://ctrlv.cz/6HTD

I'll be glad for any help