Bianpie Everything is set correctly on the signal side. I can imagine that network scanning services on your router are slowing down the traffic. I have this tip from the Internet. Another question is whether you are using an antivirus program and if so, which one exactly?
“If you recently encounter limited speed acceleration, or unable to reach maximum connection speed, please try to disable the following features: AiProtection, Traffic Analyzer, Web History, Adaptive QoS, Game boost, Web & apps filters, bandwidth monitor, Mobile Game Mode to maintain the optimal internet speed.”
Greetings
Daniele