Hello @QuantumCache
yes, I considered that. I concluded marker tags are not sufficient.
The Advantage of ADT and ADX is to give the user a broad range of query options. I as a developer can't foresee all these options. Our team decided that we want to enable the user (who is also an engineer in most cases) has access to write his own ADT and ADX Queries. As Marker Tags don't restrict access they are not sufficient for our application. No single user will be allowed access to all data. This is due to legal reasons in respect to European General Data Protection Regulation Law.
In my oppinion there is currently no solution to my usecase. So I created a feature request: https://feedback.azure.com/d365community/idea/a1fc015b-c922-ed11-a81b-6045bd8606d4