Just because the switch doesn’t require a neutral conductor doesn’t mean that a cable with only exactly one phase was pulled there. That’s what I’m trying to say. The electrician takes his roll of NYM 3x1.5mm and uses a few hundred meters of it in a single-family house. And for roller shutter switches, he then comes with a different cable, just for that purpose? That would be ridiculously stupid. But it can’t be ruled out, yes. The OP will have to check that.
then the cables from the roller shutter motor are used, they are long enough. check inside yourself. I insisted on that, and I have all three down there, but not all are installation cables, there are also thinner ones with copper strands included. those from the motor. I also paid a flat rate of 200€ more for all the sockets as deep sockets, or double deep... otherwise the bunch of Wago connectors wouldn’t even fit behind the remote switch...