I would like to host my own server. But due to the traffic any normal routers are not powerful enough. My connection to the outside is an EuroDOCSIS 3.0 Cable. I am currently to dumb to google it, any advice? My current router is a FritzBox 6490 Cable.

Are you sure that your router isn't powerful enough. I'm using a Fritzbox myself and there is no problem concerning hosting on my side.
Most of the time the problem is the upstream bandwidth. Network provider most of the time offer only very limited upstream which makes hosting at your home nearly impossible (at least in Germany).
If thats the case, the router doesn't matter at all

Upstream is nearly 20MB/s and my FritzBox is overheating, so yeah I am 100% sure that it is not powerful enough. I am talking about peek traffic (inital cloud sync) round about 200GB/day and daily average about 2GB. AVM Support confirmed that my FritzBox is overheating, since I outsourced the server everything is ok.