In App Update not showing auto Update dialog

After Creating app i have publish it to playstore with “version code 9” , then i have install it to my phone from google play store, then again i increase the “version code to 10” and publish it to google play store,
Now ,after that i have checked to play store it showing “update Button” to update my app from playstore, but in my app not showing update dialog in my app.

After that i have install the app with “version code 7” (download from kodular) , the update dialog is now appeared.

why it didn’t work with version code 9 or 8.
it is not properly work in android 10 os.

My app blocks are as below.

blocks

This block will work if you upload you app in playstore

I have already upload my app to play store and test it.