I asked my ISP and they told me that they don't limit any of my ports, so all is okay from their end.
I have two SSIDS, one is 5g and the other is 2.4g (of course. I have no guest networks. I have configured my router to use googles DNS servers (8.8.8.8). There are no QOS ooptimizations. I have a IP reservation for my pc (which im using to host Sven Coop) and my phone. IPV6 is enabled.
Something i just noticed which is probably the promblem is that my router is set to an incorrect timezone.