A new certification for a phone called the Xiaomi M1904F3BC has allegedly been found on the TENAA website. It is depicted as having triple rear cameras in a straight line aligned with a corner of its black rear panel, a waterdrop notch and a possible under-display fingerprint sensor. Therefore, the phone strongly resembles the Mi 9.
https://www.notebookcheck.net/A-new-variation-on-or-version-of-the-Xiaomi-Mi-9-may-be-on-the-way.424826.0.html