[Xiaomi Mi 9 ROMs, Kernels, Recoveries, & Other Dev] ssergiio:
For those with Assistant problems just flash this custom NikGapps and it should be OK:

https://sourceforge.net/projects/ni...sergiio-arm64-12-20220404-signed.zip/download

Here's the config used for generating it in case you want to check what's included and what's not:

# NikGapps configuration file

# If you are not sure about the config, just skip making changes to it or comment it by adding # before it
# visit https://nikgapps.com/misc/2020/11/22/NikGapps-Config.html to read everything about nikgapps

Version=20

# set this to the directory you want to copy the logs to.
# for e.g. LogDirectory="/system/etc" will install the logs to /system/etc/nikgapps_logs directory
# by default it will install it to /sdcard/NikGapps/nikgapps_logs
LogDirectory=default

# set to /system, /product or /system_ext if you want to force the installation to aforementioned locations
InstallPartition=default

# set to uninstall if you want to uninstall any google app, also set the value of google app below to -1
mode=install

# set WipeDalvikCache=0 if you don't want the installer to wipe dalvik/cache after installing the gapps
WipeDalvikCache=1

# set WipeRuntimePermissions=1 if you want to wipe runtime permissions
WipeRuntimePermissions=0

# Addon.d config set it to 0 to skip the automatic backup/restore while flashing the rom
execute.d=1

# set it to 2 if 3 doesn't work for your device
addon_version.d=3

# if you want to force the installer to use the config from gapps zip file, set below to 1
use_zip_config=0

# set this to 1 if you want to enable gms optimization, careful while doing it, you may experience issues like delayed notification with some Roms
gms_optimization=0

# Following are the packages with default configuration

# Set Core=0 if you want to skip installing all packages belonging to Core Package
Core=1
>>ExtraFiles=1
>>GooglePlayStore=1
>>GoogleServicesFramework=1
>>GoogleContactsSyncAdapter=1
>>GoogleCalendarSyncAdapter=1
>>GmsCore=1

DigitalWellbeing=1
VancedManager=1
GoogleMessages=1
GoogleDialer=1
GoogleContacts=1
CarrierServices=1
GoogleClock=1

# Set SetupWizard=0 if you want to skip installing all packages belonging to SetupWizard Package
SetupWizard=0
>>SetupWizard=1
>>GoogleRestore=1
>>GoogleOneTimeInitializer=1
>>AndroidMigratePrebuilt=1

GoogleCalculator=1
Drive=1
GoogleMaps=1
GoogleLocationHistory=1
Gmail=1
GooglePhotos=1
DeviceHealthServices=1
Velvet=1
GBoard=1

# Set PixelLauncher=0 if you want to skip installing all packages belonging to PixelLauncher Package
PixelLauncher=0
>>PixelLauncher=1
>>DevicePersonalizationServices=1
>>QuickAccessWallet=1

# Set GoogleFiles=0 if you want to skip installing all packages belonging to GoogleFiles Package
GoogleFiles=1
>>GoogleFiles=1
>>StorageManager=1
>>DocumentsUIGoogle=1

GoogleRecorder=1
GoogleCalendar=1
MarkupGoogle=1
GoogleWallpaper=1
GoogleFeedback=0
GooglePartnerSetup=0
GoogleSounds=1
AndroidDevicePolicy=0
GoogleKeep=1
Books=0
Assistant=1
YouTubeMusic=0
PlayGames=0
DeviceSetup=0
AndroidAuto=0

# Set GoogleChrome=0 if you want to skip installing all packages belonging to GoogleChrome Package
GoogleChrome=1
>>GoogleChrome=1
>>WebViewGoogle=1
>>TrichromeLibrary=1

# Set CoreGo=0 if you want to skip installing all packages belonging to CoreGo Package
CoreGo=0

# Setting CoreGo=0 will not skip following packages, set them to 0 if you want to skip them
GoogleGo=0
AssistantGo=0
MapsGo=0
NavigationGo=0
GalleryGo=0
GmailGo=0

# Following are the Addon packages NikGapps supports
AdAway=0
PixelLiveWallpapers=0
YouTubeVancedDark=0
YouTubeVancedBlack=0
YouTubeVancedMusic=0
GoogleFi=0
GoogleDuo=0
GoogleDocs=0
GoogleSlides=0
GoogleSheets=0
YouTube=0
PokePixLiveWallpapers=0
GoogleTTS=1
PixelSetupWizard=0
Flipendo=1

Also this is the latest NGcam:

https://1-dontsharethislink.celsoazevedo.com/file/filesc/MGC_8.1.101_A9_GV1zfix_snap.apk

And it's .xml for Mi9 (double tab left or right of the shutter button and select it):

https://www.celsoazevedo.com/files/android/p/f/2021/07/BSG-SLR-8.1.101.xml

@raystef66 feel free to stick it if it can help others :)