BiometricPrompt.authenticate() with custom screen

Question

I've migrated our app from the deprecated FingerprintManager to Biometric API. The app currently has a custom fragment which actually acts like the new BiometricPrompt. I would like to continue using this custom page thus not showing the BiometricPrompt. Problem is that the way to activate authentication is by creating this prompt and showing it.

biometricPrompt.authenticate(BiometricPrompt.PromptInfo.Builder()
        .setTitle("Title text goes here")
        .setSubtitle("Subtitle goes here")
        .setDescription("This is the description")
        .setNegativeButtonText("Cancel")
        .build()
)

How can I avoid displaying the BiometricPrompt and just activate authentication?

PS: On my OnePlus6T the prompt actually doesn't show because the of the device's on-screen fingerprint scanning, but on all others the prompt is shown.