Hello @Tes5in,
Sorry for the late reply. I have just tested on my XBox and I get the same latency results as you do:
I did some further testings but with speedtest.net on Edge Xbox browser against a server located in Switzerland:
As many are saying in forums, it seems the Xbox ping is done against Microsoft servers in Seattle. If you run the speedest on a Seattle located server it seems to confirm this:
The tests confirm there is absolutely no issue with the UPC router or with your XBOX. According to some articles the latency in games will depend of the game network you are connecting to. Some games have extensive gaming infrastructure in Europe where others may not.
Regarding your NAT issue, did you activate UPNP in the router?