GPS not accurate / lagging

My iPhone 6 is out of warranty and I would like to know if there is a part I can replace to get my GPS working again.

I have restored the phone and reset all network settings, I think I have tried everything in my power and can confirm it is a hardware issue.

Apple also looked at it and confirmed it is a hardware issue but I am out of warranty.

If anyone has had any experience replacing any parts to get GPS working again, I would be grateful if you could help me.

Problems experienced...

When using both Wifi and 4G data, applications using GPS (Google Maps, Apple Maps etc) my location cannot be pinpointed, when using Google maps for navigation, due to inaccuracy, it is unusable.

Thank you!