Wifi/Bluetooth/GPS are Performing Subpar - iPhone 6

Hi iFixit,

A couple of months ago, my iPhone 6's wifi, Bluetooth, and GPS took a turn for the downside after a year of working perfectly fine. I'll detail the problems with each aspect of the phone below.

Wifi - My wifi router is high speed, but my speed and the distance are severely hindered. When I am within 15 feet of the router, I typically get 3-2 bars, but when I head over to my room, which is in the rear of my house, I go down to one bar. The moment I open an application, my wifi signal drops and it goes over to LTE. I've brought other people's iPhone 6's to the same very location, and they get 3-2 bars, while I have no signal whatsoever.

Bluetooth - I can only stay connected to a Bluetooth speaker if my phone is within a few feet of it.

GPS - My GPS location on Google Maps is always a couple hundred feet off.

I've done my research, and this and this seem to be most relevant to my problems. I am not sure if they will completely solve my problems though, and I am unsure if I should replace one of the parts or both. I'd highly value any input from you guys, as I am burning through data due to my poor wifi connectivity and I cannot navigate as easily due to my GPS signal being displaced.

Thanks, Upuu