Smartphone Hardening non-root Guide 2.0 (for normal people)
https://www.reddit.com/r/fossdroid/comments/i5xj6r/smartphone_hardening_nonroot_guide_20_for_normal/
https://www.reddit.com/r/fossdroid/comments/i5xj6r/smartphone_hardening_nonroot_guide_20_for_normal/