Apple believes in your right to privacy. Here is some advice on how to use the tools it has given you to protect your privacy on an iOS device.
Use a better passcode
You probably already use a 4-digit passcode, but you can improve that with a 6-digit or alphanumeric code.
You change this in Settings>Touch ID/Face ID & Passcode, select Change Passcode and then tap the small Passcode Options dialog. Alphanumeric codes are harder to decipher, just make sure you remember the code.
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