To get back full control of your device and to extend its usage lifetime, you can install a Free Software operating system. Installing an operating system on an Android device is called "flashing". You can choose to install a complete GNU/Linux system. A Free Software alternative system based on the original Android operating system is called a "custom ROM".
GNU/Linux operating systems usually put freedom first, and their development is totally separated from the Google-dominated Android ecosystem. Even better, the code development does not rely on any other single company either: GNU/Linux systems are developed transparently by large communities around the globe with no single entity that is in control