Hi
@ItnStln511,
You should be able to go to
Settings > More > Cellular networks > Preferred network type and choose
3G instead of
LTE to tell the phone to stick with 3G as much as it can.
That should work no matter where you purchase the device from, but
that ability may be limited based on the carrier you're using. Verizon, in particular, is a CDMA network while HSPA+ is a GSM technology; a Verizon phone won't be able to fall back to HSPA+. None of the options within the
Preferred network type were able to disable LTE on my coworker's Pixel XL on Verizon.
(On a related note, this menu is entirely absent on a device using a Project Fi SIM, as all the network settings are managed by the Fi app.)