The spacebar fingerprint sensor is tied to a proprietary TrustZone binary. In an unlocked bootloader, the system loses the "secure" key pair. Even if you dump the sensor data, Android will reject it as untrusted.
Let’s be blunt: You will not find a massive library of LineageOS 21 or Paranoid Android builds for the KEY2. The PKB is a niche within a niche. blackberry key2 custom rom
is locked and has never been officially or unofficially released for public modification. The spacebar fingerprint sensor is tied to a