(France) Shower upgrade question

[tinpanalley]

We've moved into a place and there's a bathtub with handheld shower hose connected to the faucet, as is typical in bathtubs here. Then they've just put a shower head holder on the wall. So we want to install a shower column without taps.

What I want to install:
I got this, and it's perfect, but now I'm afraid it feels heavy. Is that a thing, a shower assembly being too heavy for a wall?
The whole thing when assembled is 2.4kg. The overhead shower head, which is the one if you look at the images below that protrudes out, is 1.45kg alone. So that's what I'm dealing with, but I know the integrity of the wall and the type of force is more important than the weight capacity of the anchors. On wet sponge, anchor tolerance is pointless.

Just did a wall measurement in an empty part of the wall and the wall is 1.75cm / .75" thick, the gap between the shower wall and the next one is 4.5cm / 1.8". And the tiling is about .6-.7cm thick. But the plastic toggle bolts I have need about a half inch hole and I don't wanna do that in a shower.

What anchors do I have:
I've got good quality 40 and 30lb DuoPower anchors I use (yes, they're North American though we live in France, we've moved recently...). I just didn't know how much tension load would affect this installation.

So, I'm confused about whether this all sounds fine with my anchors, do I need something else, is any other info needed to help me out?

The device:

 

[yorksbuilder]

Give more clarity about the wall construction and then we can advise accordingly. Is it plasterboard, cement board, wood stud or metal stud, is it brique (hollow terracotta)?

 

[tinpanalley]

Give more clarity about the wall construction and then we can advise accordingly. Is it plasterboard, cement board, wood stud or metal stud, is it brique (hollow terracotta)?

I genuinely have no idea. But.. I've taken a couple of photos with my endoscopic camera and a video. No clue what I'm looking at. Did I just happen by chance to find myself in this hexagonal air pocket in the wall?! And what is that material? Some kind of internal foam? All I see when I turn/rotate the camera in there is the same white material. I was hoping to see a stud in an empty wall that I could aim for from the outside.

Here are the photos and a video.

 

[yorksbuilder]

Looks like hardboard with egg carton internal. Not really suitable for a bathroom, I'd recommend ripping out and refitting cement board or at a minimum moisture resistant placoplâtre before hanging your shower on it

 

[tinpanalley]

Looks like hardboard with egg carton internal. Not really suitable for a bathroom, I'd recommend ripping out and refitting cement board or at a minimum moisture resistant placoplâtre before hanging your shower on it

Right, well that's not gonna happen because this is a rental in a rather prized apartment residence actually. Surprised to find this may be inadequate materials.