For most organizations, migrating to a newer version is the best path forward. Windows Server 2019 or 2022 offers vastly superior security, integrated cloud capabilities with Azure, and better support for modern hardware. If your hardware is older, consider a lightweight Linux distribution or upgrading the physical components to support a modern Windows environment.
After these four items, your "winver" will show Version 6.1 (Build 7601) with no further updates available. Windows Server 2008 R2 Standard Sp2 Download X64
If you actually need the SP2 for the older non-R2 version, it is available as a standalone update via Microsoft (KB948465) . For most organizations, migrating to a newer version