Super slow WiFi speed on iPhone?

I’ve replaced my WiFi router twice in the last month. The old one died and the new replacement was transmitting very slow speeds over WiFi.

So today I changed from the Netgear ac1750 to a Linksys ac1750. I did a speed test and I’m still getting like 0.5-2 mbps over WiFi, but my girlfriend is getting like 40-50mbps in the same room at the same distance.

Is the WiFi card in my phone dying? Is there anything I can do? I already tried restarting my phone and resetting my network settings.