Hmmm, maybe I have an additional issue besides he FP6 issue 
Or claude messed up entirely here 
I did a bit of research and learned that Fritz!OS (and other router-firmwares) consist of binary blobs with Wi-fi-firmware that come from the manufacturer of the Wi-fi chips. So afaict, it is possible that our routers share the same bug if they consist of the same buggy blobs because their Wi-fi chips are from the same manufacturer. That might be an explanation but I have doubts.