My AC1200 wifi adapters speed is fluctuating

Hello. First time poster and at this moment not satisfied with this product, but we shall see if it can be delt with.

My old D-Link DWA-140 Wifi adpater burned out after 10 years of service. It has served me very well and it has shown that cheap doesnt neccacarily mean bad. Anyways, as it was burned out, I set out to the same store I bought many years ago, only to find out they no longer sell those. Instead they sell Netgear wifi adapters, so there was 3 or 4 models available. To not dissapoint myself, i bought the most expensive one they had, a AC1200 model A6210. After 3 hours of troubleshooting to install it on a windows 10 computer i finally managed to awake the device, and log on the wi-fi. But the latency and speed is sadly supbar to that of the D-link. It is even closer to my router than the D-link.

What i would like to know is what differs from this device compared to my old and is there any remedy for this sort of problem? Loading webpages and latencies in games are sometimes so high i ping out.  The signal is ok in the genie, it has a 72Mbps which is more than my old one.