You could start by checking a few settings.
Are Secure User Plane Location (SUPL) and Predicted Satellite Data Service (PSDS) deactivated?
Both can be found under Settings> Location
and greatly reduce the time that GPS needs for initialization.
A good overview of what these connections do and how they work can be found here:
https://grapheneos.org/faq#other-connections
The other steps are well explained in the link matchboxbananasynergy posted.
If I may summarize it casually: The default configuration is the more privacy-friendly one, the alternative to which you are offered the step-by-step instructions may be the one that responds faster.
If you have difficulty finding some items in the menu - the main settings are located in two places:
Settings> Apps> Sandboxed Google Play
(e.g. Google Location Accuracy and Reroute location request to the OS).
and Settings> Locations
(e.g. SUPL, PSDS and Location services (Wi-Fi + Bluetooth scanning)).
If you still have questions, this discussion may also help you:
https://discuss.grapheneos.org/d/7098-optimal-location-accuracy-settings-for-privacy