Hey,
You are right, ADF supports only reading from sharepoint via web activity and doesnt support write back as REST end point is not supported as sink.
In case if you need low code technology, then Azure logic is the best fit which supports reading and writing back into sharepoint.
Others Azure offerings like Azure functions, Azure databricks, Azure automation and Azure batch support custom code and based on custom logics , you can read and write from sharepoint based on the code you write