How Should We Be Making Our Phone Contacts Private?

I am using stock Samsung Contacts to store phone numbers and was in the middle of transitioning to Open Contacts from fdroid.

I noticed there was another app called Simple Contacts from fdroid as well. What is the difference? Is one more secure than the other?

I also see there is a service called etesync that encrypts contacts, calendar, and tasks. Do I need this if I use Open Contacts or is that good enough?

making phone privacy