@Petr Klekner - Thanks for the question and using MS Q&A platform.
MS Fabric is currently not supported in the Q&A forums, the supported products are listed over here Supported products on MS Q&A (more to be added later on).
You can ask the experts in the dedicated MS Fabric community forum.
Can you please open as a new thread in MS Fabric community: https://community.fabric.microsoft.com/t5/Power-BI-forums/ct-p/powerbi
Hope this helps. Do let us know if you any further queries.