anyone else having problems with pokemon go? (gps, gyroscope)

I never have had any problems using the phone gps on my car with maps but man my gps is really imprecise while walking and playing pokemon. My character is often stuck or randomly walks even if I'm perfectly still. AR doesn't work at all but I read this is because this phone doesn't have gyro (it was a 2015 0 device and no gyro?? c'mon..). I'm starting to wonder if my gps is faulty. I don't have covers on my phone, already set high accuracy gps in settings and I already reflashed the firmware then factory reset and is still the same.

Do you have any problems with this? I know pokemon go is still pretty buggy but everyone I know is playing it without these major problems. Also, how amazon warranty works if I bought the phone from amazon.fr but I live in Italy?