This can come with a heavy price depending on how reliant you are on big tech services. If you can do away with Google Maps and do not require a ton of specialized applications it can be done without to much lifestyle change. However if Google Maps is a must then this can not be done.
The easiest, most-user friendly way to take privacy back on your cell phone - is to use mainstream hardware with open source software. This works out well when projects like GrapheneOS exist. GrapheneOS is a de-googled version of Android. What this means is that it looks and feels exactly like a standard Android phone, except the parts that Google adds to the operating system to track you and harvest data have been left out. Google achieves this level of tracking by installing their suite of software prior to distribution. This installed software, has all the data harvesting bits in a closed-source set of apps. This includes; Google Maps, Gmail, Google Drive, and most notably – the Google Play Store. This means the source code that make up the operating system is publicly published can be audited by the world for spyware as well as data harvesting. Android, on its own, without these apps is a very private open source alternative. This means the source code that make up Android is publicly published, and can be audited by the world for spyware as well as data harvesting. However, without Google's apps you may find the phone is less than useful.
So what is the solution? The individuals at GrapheneOS have created a hardened security minded version of Android with zero Google software on it. It is by far the most secure mobile operating system that is easily accessible. I know what you're thinking, how can we use Android without a play store? Fortunately open source only 'play stores' exist. F-Droid is one of the most popular, and if your application needs are not too specific, you can generally find a good open source alternative in the F-Droid store.
Pinephone - the Pinephone is an excellent example of near 100% privacy in software and hardware but the lifestyle cost is fairly steep. This is a major lifestyle change but really covers all the angles.
The last thing to think about is this; If you couple a GraphenOS Pixel (Pixel is chosen by GraphenOS exclusively for its hardware security features) as well as a Home Cloud from [Ctrl]Sync you can get a very usable eco-system that feels like a traditional Android phone - with all the cloud features we all have grown to expect without any of the data harvesting, and spyware.
-[Ctrl]Sync Team