ᐅ Wall panels for an existing shower.

Hello,

We have an old shower with cracked grout. I don’t want to do a complete bathroom renovation, so I came across these wall panels that can apparently also be installed on the inside walls of the shower.
I’m not sure if they are made of a composite material. Sometimes I’ve also read that they are made of aluminum.

Is this a good option? Can it be done as a DIY project? Is it permanently watertight?
How exactly does the installation need to be done for it to be a reliable alternative?

Best regards

It would be really helpful to know if any experts here have already installed these themselves or if some might be using them in their own showers.