A new Xiaomi patent for an "electronic device" has given an idea of what the heir apparent to the stalled Mi Mix line could look like or what it could feature. The potential Xiaomi Mi Mix smartphone in this patent has a slider mechanism that can be voice activated, and it has a display that wraps over the bottom edge and onto the rear side.
https://www.notebookcheck.net/Mi-Mix-heir-apparent-could-end-up-with-voice-activated-slider-and-semi-wraparound-display-if-based-on-latest-eccentric-patent-from-Xiaomi.517037.0.html