Question about Devolo Magic 2 LAN DINrail

Yes, but depending on the distance, pull the fibre optic cable (?) into the house and Devolo into the sub-distribution/house panel. That's how I did it and it works without any problems.

Basically yes, I have a similar constellation with 2x DINrail. However, the throughput is strongly influenced by the cable length, interference on the network and contact transitions in the cable path.
PLC connections are sometimes a matter of luck when it comes to stability and throughput, so it's impossible to give a reliable answer without having tested it. It's a case of trial and error.