@Völker, Florian Thanks for posting in our Q&A.
For this issue, it will not affect intune. If an app is unapproved or deleted from the managed Google Play store, it will not be removed from the Intune client apps list.
It still doesn't affect the app that has been deployed to the device. From the google article, it shows it isn't available for new users to find and download this app in managed Google Play, but existing users can still use them.
https://support.google.com/googleplay/work/answer/9146439
Note: Non-Microsoft link, just for the reference.
Hope the above information will help.
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