The fairphone should have privacy features. Calyx OS should be the default operative system. It is very private and secure and fast! It has many piracy features that i cant be bothered to write them all here. Many phones spy on their users and thats unfair. Fairphone should have Calyx.
Also. Hardware kill-switches should be in the hardware. This will ensure that no background tracking on hardware level is going on!
Thats your preference and other user have other preferences and Fairphone can hardly cooperate with all available ROM developer. So Fairphone has a collaboration with Murena and Calyx OS is available through community efforts, so the user has all options. And reg kill switches see e.g. here
Hardware kill-switches are not an easy task. To address privacy purposes here you would also need to separate the modem from the processor and more which makes phones really expensive. Read dedicated articles about Librem phone efforts for kill-switches.
Fairphones goal from beginning on were fair sources (mining, social welfare, longer lasting products, read more in Our Mission - Fairphone) which is already a challenge and I find important as well.