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Since it is within LAN it should load ~1-5 s. Clicking on anything of the webinterface takes a lot of time to load, same goes for the router. I think it is somehow a DHCP server issue? Pihole is my DHCP server, nothing else runs on it. The average load is neglible ~0, memory usage <10%.
Takes a long to open programs hosted on LAN, also going to router settings loads painfully slow. Any website on LAN is slow. Acessing WWW also feels slower, but not sure though.