Bought an HP Envy 13, wifi almost not working

I've bought an HP Envy 13 (4k screen, 8gb ram, i5) and I'm loving the machine, but! I've got a problem. A huge one.

The wifi reception is garbage. I have to be 2 meters from the router for it to be usable, which makes the device really useless. What could be the problem?

This one was on store display supposedly, so it isn't new, but why would it work like this. :(