rbr50 v2

I have an RBR50v2 with one satellite the firmware is the latest available.  The router is connected to our HTC fiber to premises modem device via its ethernet port.  We pay for 300Mbps speed up and down.  Using the Orbi Admin login I can see that we are getting at least 299 Mbps from  the HTC Modem to the Orbi.

 We used to get a consistent  292 Mbps on wifi.  Everything was working fine for a year and a half until we had a power failure with several attempts from the power company to get power restored.  Now our Wifi speed is horrible and fluctuates from nothing to less than 50Mbps with frequent drops and hangs.  HTC ran their tests and state that their equipment is working without issues.  Connecting to our Orbi via lan ports gets poor connection issues also.  The Orbi router is connected to a Netgear 8 port 1Gb Switch then to the house wiring to various rooms via cat 6 wiring installed by the developer.  Our Orbi satellite is connected to that switch from its lan port, through the house wiring also.

How do I go about testing the equipment to see where our slow and unstable internet connection is coming from?

I have tried rebooting all of the equipment in I hope, the proper sequence ie everything unplugged restart HTC Modem, wait for its connection and solid lights, restart Orbi Router, and wait for it to boot and verify internet connection to HTC Modem, Reconnect Orbi Router to Netgear switch, wait for Switch to power up and Lan Connection Lights, Reconnect Orbi satellite, Restart Laptops, verify internet connection via WiFi and Lan, Speedtest by Ookla for both wireless connection and Lan.  Satellite in same room as laptop varies from 9 Mbps to less than 50Mbps and still dropping connection.  On lan 90 Mbps and still drops connectivity

I am going to try a factory reset of the orbi"s next. 

Any Thoughts?  

Any test equipment a homeowner could use, that would be better than just a plain Jane $29.00 cable tester without breaking the budget?

Thanks in advance for your help,

Mark

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