How to change photo storage path for LineageOS 16's Camera app?
As of right now it is not possible for you to change the path. Android Pie does not allow apps to write/read SD Card public area and only allows apps to access the application private area.
That being said inside of Lineage OS Gitlab Repository there are several discussions to fix this problem. Maybe it will be fixed in the future with an update of Lineage or the integrated camera App.