On both china and global versions of MIUI, you cannot import themes normally. By following this guide, it’s possible to pass that restriction.
Apparently a china MIUI user reported that using MIUI China Beta 21.12.4 bricked their device out of curiosity.
Xiaomi has restricted MIUI 12.5 features to devices with MIUI 12.5 Android 10. With this module you can unlock all the features.
MiuiHome [LSposed module] Xiaomi has released alot of new features inside