If you don't want to use the WLAN stick somewhere else, I can only agree with the previous speaker. I have installed this adapter ASUS PCE-AC56 (PCI-E x1, 866Mbit/s, 450Mbit/s) and it works perfectly in two systems.
https://www.digitec.ch/de/s1/Product/435748 I have attached this to my mainboard and am more than satisfied with it. I don't recommend a real wlam stick via usb because the transfer rate is too low.