Deconection issues and low speed internet

Hello, 

I have serevar issues with this product (NetgearA6210) sometimes it deconects by itself and/or have a very low uploas and dl speeds (screenshot of speedtest below) . I've tried reinstalled the latest drivers from here : https://www.netgear.fr/support/product/a6210.aspx#Version%20du%20logiciel%201.0.0.39%20(compatible%20Win%2010)

(i have installed only the driver, not the netgear app) It didn't help.with my laptop on wifi at the same place i get 200mb up and 200mb down

Any ideas ?

Have a gread day !