For Windows Server 2019, the Microsoft Report Viewer 2012 Redistributable is required. The SQL Server System CLR Types for SQL Server 2012 are required for the installation, these are part of the Microsoft SQL Server 2012 Feature Pack. There is no need to download and install the complete package. The MSI SQLSysClrTypes.msi is sufficient (for Germans: take the English version, the MSIs can be loaded separately)