The actual download size for "all" workloads is ~35-50 GB depending on optional components. Use the Visual Studio Subscriptions portal (formerly MSDN) to get the legitimate vs_enterprise.exe bootstrapper for version 2019.

If you don't need every component, you can save space by adding only necessary workloads.

vs_enterprise.exe --layout D:\VS2019_Offline --add Microsoft.VisualStudio.Workload.NetWeb