The camera will be in the same place as in Mix 2. This is s version so there will be no major changes on the outside.
Here you can see the front of Mix 2s:
https://www.gsmarena.com/xiaomi_mi_mix_2s_official_teaser_no_selfie_camera_on_top-news-30155.php
Maybe that corner cam will be in Mix 3.
How to disable the navigation buttons on the lock screen wallpaper carousel? Really annoying that I cannot press the carousel buttons because the nav buttons always go on top.
You can see the problem here on the bottom of the screenshot: