GPS taking long time to fix out in the open
The first thing that comes to my mind is that a first fix starts with unknown position and with unknown time. The device has to find as much satellites and then calculate the position.
All the subsequent fixes are easier to find, because you already have an approximate positon and you already have the correct time, then a GPS tracker would spend less time to lock in, by doing a Cross-correlation of known sattelite sequence and received signal. But in case the initial conditons are not met (no approximate position or no correct time) it has to do the first fix, every startup.
Make sure you have a battery backed RTC time and position, and a kind of mechanism to upload the initial conditions to the GPS receiver at startup.
EDIT:

Looking at datasheet, the SoC has a BBRAM - Battery Backed RAM, but there s no mention about the battery neither it has any pad to connect an external battery. Probably it has an super capacitor or small LiPo battery embedded in the module. It could be that this battery is empty, since it is new device. Try to power the device for couple of hours or the entire day, because that battery would charge very slowly.
Once it will be charged try to see if the fix comes within specific time.
EDIT 2:
I think I have found the root of the problem read this:
17.2. POWER SUPPLY
It is recommended to keep the power supply on all the time in order to maintain RTC block active and
keep satellite data in RAM for fastest possible TTFF. When VCC is removed settings are reset to factory
default and the receiver performs Cold Start on next power up.