Locking your phone or wallet with password or applocks does not guarantee security to your wallet because they lock you're using are only protecting your device from another user having access to your wallet or apps but when they have access to your private keys or seedphrase alone, they can steal your coins and have access to your wallet without them using any password since they can use those keys and seeds to import your wallet on any device as long as they are not using your own device, in case of using other devices as well for protecting apps, ve careful not to introduce malwares from any unreliable source, you can make use of password or 2FA for security measures.