This app was mentioned in 11 comments, with an average of 1.27 upvotes
Download and install this app https://play.google.com/store/apps/details?id=com.iglint.android.screenlock
Go to the apps box, you will notice that 3 apps were installed, this are Admin Lock, Screen Lock and Smart Lock
Open screen lock and turn on both Device administration and Fix biometric unlock
Go to personalization, Tap on animation and select "TV style" (I don't know why but for me the animation "Old TV Style it's not working, it may work for you, but I don't know)
Go to Bixby, tap the 3 dots, go to settings > Bixby Key
Select Double press to open Bixby, then turn on "Use single press"
Press Select app and find "Smart Lock"
That's it, now when you press the Bixby button once, you will have the animation
Unfortunately, the animation duration it's a little slow, but to change this, you will need to buy the Pro version (1.99 USD) but this is an Android, so you probably know what to do if you want it for free :)
I'm doing that without root. I'm using this app: https://play.google.com/store/apps/details?id=com.iglint.android.screenlock
It has a Nexus Imprint mode that works without needing the pin code. Basically, after you double tap or do whatever gesture it is to launch the shortcut (for those who download it, you need to set your gesture to launch the shortcut in the shortcut menu, not the app in the app menu), it turns the screen black, however the screen is still on for the next 10 seconds or so, at which point the display actually turns off. Then just a fingerprint is enough to unlock directly to the home page.
I use Screen Lock - On Off Button because it has the feature to change the unlock sound. I notice sometimes the VL gets a little crackly but that's usually after my phones been asleep for a few hours.
This app will do it (along with a ton of other animations). Pretty sure you have to use the app to turn off the phone to get it to work:
https://play.google.com/store/apps/details?id=com.iglint.android.screenlock
I have used this app on all my devices. Reduces the use of the power button and works with the biometric security.
I use this to turn off the screen: https://play.google.com/store/apps/details?id=com.iglint.android.screenlock
I use the paid version. This app is nice because it works with the biometric locking.
Between this, double tap to wake, and tilt to wake, I never touch the power button.
Ok finally found a solution to this. The only 3rd party screen lock app that allows fingerprint unlock is called Screen Lock Pro by Prahallad.
In the app setting, make sure to enable "Smart Lock and Nexus Imprint." (only available in the pro version)
Then just link Nova's gesture to this app shortcut and everything works as normal.
change the stock screen lock https://play.google.com/store/apps/details?id=com.iglint.android.screenlock&hl=en_US