Apart from the slew of additional features already on offer, MIUI 12 is also slated to get a nifty functionality that allows per-app volume control called Sound Assistant. Meanwhile, Chinese variants of the Mi 9 Transparent Edition, Redmi K30 5G Racing Edition, and the Mi 10 Lite Youth Edition have now started receiving the MIUI 12 stable ROM OTA with global rollouts expected soon.
https://www.notebookcheck.net/MIUI-12-brings-Windows-like-Sound-Assistant-Mi-9-Explorer-Edition-Redmi-K30-5G-Racing-Edition-and-Mi-10-Lite-Youth-Edition-snag-official-MIUI-12-stable-updates.477187.0.html