Freckles222 You can make Google Maps ask you for location and network permission every time you open the app. And whenever you don't need the G.Maps specific features you can use something like Organic Maps or Magic Earth instead, which pull their maps from https://www.openstreetmap.org
The ability to set permissions for each app on GrapheneOS is one of the best features it has, and it only gets better over time. There are tons of discussions about this if you use "Search Forum" on top of the page here.
When you have bought a phone (recommend Pixel 6a, and buy from Google), just take your time and do one thing at a time. You don't need to move your SIM card to it before you start install apps that require it, like (some?) banking apps. Search for alternative apps and ask for help when needed. Better to be safe than sorry.
Use your iPhone in peace until you feel you have built up your new phone enough that your life won't suffer if you move over the SIM card. THEN install those last apps that require the SIM card.