as you can see row level security is supported in Fabric
https://learn.microsoft.com/en-us/fabric/data-warehouse/row-level-security
The link you have added is about Dataflows Gen2
and
there are no RLS permissions available for Dataflows
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The following page says that RLS is not supported in Fabric, but as per latest blogs on Fabric, that is not true. https://learn.microsoft.com/en-us/training/modules/use-dataflow-gen-2-fabric/2-dataflows-gen-2
as you can see row level security is supported in Fabric
https://learn.microsoft.com/en-us/fabric/data-warehouse/row-level-security
The link you have added is about Dataflows Gen2
and
there are no RLS permissions available for Dataflows