How can I unlock a locked iPhone with unresponsive touchscreen?

If your iPhone says it is unavailable, see what you need to do here --> If you see a iPhone, iPad, or Apple Vision Pro unavailable message or Security Lockout screen - Apple Support

If you see a message your iPhone is disabled, see what you need to do here --> If you forgot your iPhone passcode or your iPhone is disabled - Apple Support

If your touchscreen isn't working, there is no way to unlock your phone.

Make an appointment at the Genius Bar to have it repaired.

Genius Bar Reservation and Apple Support Options - Apple