i'm not trying to argue with you or refute points you made, but instead to respond them in the context of the OPs question:
I want and have wanted to get rid of a bunch of proprietary software in my life, including but not limited to Google’s software, for quite a while now, and I even got a Pixel 7A with hopes of installing GrapheneOS.
my parents are understandably concerned and need me to use Google Maps’ location sharing whenever I go to school. All my classmates use Instagram and we have that as our only messaging platform. I currently use DFInstagram, but I feel that it is not free from spyware. Finally, I also own a DJI Mini 3 Pro, and the associated DJI Fly app just refuses to work under GrapheneOS (I tested). Is there anything I can do to replace or limit the access of these aforementioned proprietary apps?
so graphene isn't an option and the OP wants to get some control over google maps location sharing, instagram and be able to use their drone app.
ios has straightforward privacy controls that accommodate family sharing with a decent degree of granularity, can limit what applications like instagram can do in a very clear and easy to understand way and as far as i know the DJIFly app works on ios (its in the app store and has 4 stars. i don't use it so i can't speak to it).