I have the following setup: Microwave ISP -> Orbi Wireless router -> Macbook as only wireless user

I have bugged the ISP to test their speed many times and it is always >20mbps

I have measured the speed before the router with both my computer LAN directly from modem and using the routers built in speed test. It is always >20mbps

I have unplugged all other devices from the network. My laptop is the only device. I never get >20mbps. I generally get <5mbps and often <1mbps. I have also tried testing on my phone and I get the same speeds.

I am not even sure how to go about beginning to diagnose this issue. I have already replaced the router. I used to have an older apple airport extreme. It had the same issues.