For this to work on single-user clusters you need the Filtering Fleet enabled which requires you to enable Serverless Compute (same infra as Serverless Workflows / Notebooks / DLT).

https://docs.databricks.com/en/release-notes/product/2024/october.html#fine-grained-access-control-o...

" In workspaces enabled for serverless compute, if a query is run on supported compute such as single user compute and the query accesses any of the following objects ..."