Dell Latitude 7310 and 7320 extremely poor wifi performance

Dear,

I have new corporate 7310 Dell Latitude. I work in a room 5 meters from the router where all old devices get 80Mbps. New Dell with Intel chip Ax201 160Mhz gets 1-20Mbps unstable performance.  Impossible to have video call on this connection.  I spent hours with my corporation IT Support , reinstalling , configuring laptop, my router and then the same with Dell support. Dell finally decided to replace the machine as the conclusion was this must be a broken machine. The new Dell came - newer model 7320 and it has exactly the same problem.

So far it looks like this computer has an extremely poor wifi  (or chipset or antenna design).  I still come here with a hope that somebody has a solution.  I hope we are not in the times that new equipment comes with worse performance.

Dell support, other users - please advise, please help.