@abcdw I am also looking for more privacy friendly, preferably open source, apps for my Android phone.
For maps I use the free version of Locus Maps for hiking (offline maps) and for navigation I just came across Magic Earth, but I haven't used it much yet.
For calendar I use the great encrypted calendar that comes with @Tutanota email.
I recently switched to the OpenBoard keyboard and very pleased with it!
Still looking for a good photo sync service as well 😊