Since 4.8.1 is the actual current "solid" version you likely need, here is a quick breakdown based on technical reviews and Microsoft's documentation :
The offline installer is approximately 249 MB in size for the 32-bit version and 287 MB for the 64-bit version. .NET Framework 4.9 Offline Installer for Windows
If you are a developer, it is important to note that while .NET Framework 4.8.x will be supported as long as the parent Windows OS is supported, it is no longer receiving new features. For modern app development, you should look toward or .NET 9 . These versions offer significantly better performance, cross-platform support for Linux/macOS, and the latest C# language features. Since 4
Avoids installation interruptions caused by fluctuating network speeds. Learn how to enable
offers step-by-step instructions for installing on various Windows versions. Learn how to enable .NET Framework 3.5