This should resolve your issue.
Go-ahead and restart after and check to be sure. It shouldn't change anything you will notice unless you use tts for calls.
Please check this post as "solution" if it fixed it so the next guy can go straight to this post. Let me know
Hello @GTumms ,
All Unlocked devices should be able to receive One UI 4 update at this time. Update was opened for carriers in two separate rounds based on CSC which may have caused some of users to receive an update before others.
Please call us at 1-800-726-7864 if you are still unable to update to One UI 4.
One UI Beta Team