The Mi A3 is now receiving a new update. The update further fixes the issues from previous Android 10 builds, including fingerprint and launcher problems. Most notably, though, it allows the shutter speed to be set to a max of 32 seconds like it was on Android Pie.
https://www.notebookcheck.net/New-Mi-A3-update-fixes-shutter-speed-issue-in-Pro-mode.464644.0.html