Firmware.

When you say your speeds dropped ? Did you lose access to 5g ? Did you get bumped to lowest 4g to b12?

If so then the firmware corrupted your unit & you will need to get it replaced . I had two units broken by firmware 1.00.18 & am on 3rd one.

Others had posted similar issues,  while others had no problems. 

My 3rd unit just got the update & working other than being on b66 I am now on b2 for 4g , but still have 5g. Strangely my ip address changed to Puerto Rico. I am in socal.  It was really crazy because I was being. Served Spanish adds & my Google searches where all in Spanish.  I was able to get a local  ip back in USA after physically unplugging the unit.

The thing I noticed about my 1st 2 units that firmware 1.00.18 broke was the sim card door was hard plastic & super hard to open. My 3rd unit, the door is soft rubber & easy to open. 

 So there could be a production run where certain units are fracked by the update & other units update with no issue.