1. Remove Google account and any kind of screen lock (fingerprint, PIN, pattern, etc.) from your device.
2. Eject sim card from your device.
3. Reset your device. In setup wizard, skip everything, don't connect to WiFi, don't add fingerprint or any kind of screen lock.
4. Go to Developer Options and enable USB debugging.
5. Connect your phone to PC.
6. Open CMD in adb directory and type
adb shell pm uninstall --user 0 com.android.phone
8. Connect to WiFi, open Chrome and go to google.com (or any website really).
9. Go to Developer Options and enable OEM unlocking.
10. Reboot into bootloader and via CMD run
fastboot oem unlock
fastboot flashing unlock
Be aware that unlocking bootloader removes everything from your device.
Credit to members LeoTheRomRasta and Qu3ntin0 for making this method available to the community on the Bounty thread yesterday. https://forum.xda-developers.com/pix...3740911/page14 There is an ongoing discussion there about variations on this method.