MR80 wireless wifi slow after fiber install

Hello everyone. So I have a nighthawk mr80 with 2 satellites. I was hoping someone could help me with our wifi speeds. We had 400mb cable and I havent had any issues. My wifi speeds were 400mbps or close to it. We just got 1gb fiber installed today and Im getting 900 down and 800 up hardwired to the main hub. When I check my wifi speeds I get anywhere from 10mbps to 120 to 300 all over the place but still no where near where it should be and regardless of the speed test the internet is significantly slower. Its almost like its capped b/c when I get the 120 I can do a test again and itll hit 120 several times in a row.  Ive tried rebooting the router to factory default and I tried setting it so we have the 2.4 or 5ghz and the 2.4 was 10mb where the 5ghz is what made the speed jump up to 300 but as I mentioned its not very consistent. The router has the newest firmware as well. All of this is me right in front of the main hub btw. If I run upstairs directly above the main hub the speed drops down quite a bit.. Im not sure what to do as my cable worked just fine so I really dont know why having fiber installed would make it drop speed. I would appreciate any feedback to help me get this squared away. Thank you!!