It's is not optimised on the Poco X3 pro and many other devices. When there a incoming call, sometimes the caller informations don't appear on the calling interface. The Phone UI is very laggy. It's not solved yet. Sometimes I use to see phone app is stopped responding. I don't know why the Phone app developers are not optimising this as well. But you will notice a great optimisation in almost every high range device (35k+). The smoothness is there in those devices. Please solve the issues.