After a reboot (if required), verify .NET 4.8 is installed:
The offline installer is a standalone package (approx. 116 MB) that includes all necessary components, allowing you to install the framework on servers without an active internet connection. Microsoft .NET Framework 4.8 Offline Installer Alternative Support Page: Microsoft Support KB9d23f658 Installation Requirements for Server 2016 .net framework 4.8 offline installer for windows server 2016
Yes, for advanced deployment, you can add the offline installer to an answer file (unattend.xml) using the Microsoft-Windows-NetFx4 component. However, in most cases, post‑OS deployment with the standalone installer is simpler. After a reboot (if required), verify