generic Incremental model to load multiple table

The problem I’m having

What i am trying to achieve here is , trying to build a generic upsert pattern / Model which can be used in any no of times to load multiple target tables.
Have a data in source table A and i need to do some transformation of data and i have to load the transformed data into Table B with upsert strategy.
Same way i have different source table and different target tables and i want to use the same upsert strategy to load these tables

The possible scenarios would be
I might want to use the update strategy same time multiple times
Source tables A , B , C … might load at same time and i want to load this source data in parallel using same upsert strategy.

The context of why I’m trying to do this

What I’ve already tried

Some example code or error messages

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