Realme has announced the Realme UI 3.0 open beta program based on Android 12 Realme X3 in India which launched in June 2020 with Realme UI based on Android 10. Those interested in getting a taste of Android 12 and Realme UI 3.0 on their X3 can apply for it by going to their smartphone Settings > Software update and then tap on Trial version > Apply nowand submitting the required details. If your application is accepted, you will receive Realme UI 3.0.
However, keep in mind that since this is a beta version, it may contain bugs that could spoil the user experience, so it is better to avoid it on the primary device. If you still want to try it, make sure your X3 is running firmware version RMX2081_11.C.13 or RMX2081_11.C.14 and has at least 60% battery and 5GB of free space before installing the open beta update.
For more details about the Realme UI 3.0 Realme X3 open beta program, you can go to the source link below.