Recent reports claimed that Xiaomi has planned a QHD+ display for its next flagship device, the Mi 11 Pro. New information in the form of MIUI 12 code has further lent credence to those claims, and it appears that Xiaomi is, indeed, set to offer a QHD+ display on a smartphone for the first time.
https://www.notebookcheck.net/Latest-MIUI-12-code-lends-credence-to-reports-of-a-QHD-display-on-the-Mi-11-Pro.505798.0.html