Security question incoming calls I've got an Nokia 6 with Pie! How do I stop others from answering my calls, or more correct, how do I stop incoming calls from opening my phone?? Everytime there's an incoming call, all security settings are set aside, and anyone can answer or have access to my phone.
You can use Incoming Call Lock. When you start the app: 


  This application will protect your phone's Incoming call to be picked by some one else. This application will not allow any one to see the caller's number, name or any other details as the password input screen will be up on the screen.



Give the necessary permission.
Set a pin or pattern to unlock the phone when people call.
Enable the lock.


When you receive a call, before answering, you will need to enter a pin or pattern.

Note: In the settings, you can fine tune how the app should work. You can block all incoming calls or some, allow to view the number that is calling or not, etc.

Important: @Izzy has pointed in the comments that the app has severe privacy issues due to several trackers incorporated to the apps that may transmit your data to 3rd parties. Plus some permissions look suspicious. See his comments below.

Disclalimer: I am just a current/former user of the app(s).