Well this trick works will all samsung device who has in-display finger print sensor .you’re not happy with its speed, there’s a new trick you can try to improve your sensor’s
To try out this ‘fingerprint speed **bleep**,’ open Settings, go to Apps, tap the 3-dot menu button at the top and select Show system apps. Next, search for com.samsung.android.biometrics.app.settings and select it. Go to Battery » Optimize battery usage and make sure you have selected All apps from the drop-menu at the top. Search for com.samsung.android.biometrics.app.settings again and tap the toggle to disable this function. Reboot your phone to apply the changes. Just make sure you’ve waited until the phone fully rebooted and all the apps have loaded to determine if your sensor is or isn’t faster than before.
If you still have doubt or not understood then follow the instructions in giving link below :
