Which Intel NUC to choose?

Bought a NUC 7i7 a couple of years ago and used it to host ROCK and do several DSP jobs. Ran like a charm - until I changed my router. With all remaining devices and settings being the same, my NUC refuses to show on the network. Room support did not help and now I may have to reinstall everything from scratch, which I am dreading. My new router is a FritzBox so be aware, these devices can conflict with a NUC. Only heaven knows how.