After creation and publishing of the new report faced with trouble of scheduled data refresh configuration:
You don't have any gateway installed or configured for the data sources in this dataset. Please install a new personal gateway or configure the data source for an existing data gateway.
Report has two data sources -> MSSQL and Excel file. (I never used Excel file as a source before)
Both data sources(MSSQL and Excel file) require a gateway(on-premises or personal) in order to refresh datasets on Power BI service. So you may need to install a new personal gateway or configure the data source for an existing data gateway(on-premises) in your scenario. For more details, you can refer to the following articles.