Reading books, playing sports, camping, fishing, going along trails are activities that compromise your private data the least.

Having your phone off is probably the best way to stop all tracking. If you do need to make or receive calls over a mobile then obviously you will have to give up total privacy. GrapheneOS and MicroG services for Android, phones such as the Librem, PinePhone are open source solutions with privacy in mind.

I leave my phone at home whenever I can. If someone needs to contact me, they can leave a message on my voicemail. I understand that some people may not be in a position to do this due to family/work.