If you have dotnetfx35setup.exe , you can extract a true localized offline installer:
: Microsoft's central hub for .NET 3.5 SP1, including web and offline versions. Installation on Modern Windows (10/11) net framework 3.5 sp1 offline installer
DISM /Online /Get-Features | findstr /i NetFx3 If you have dotnetfx35setup
that can be "produced" (enabled) using local installation media rather than a standalone Microsoft Learn How to "Produce" the Feature Offline (Windows 10/11) If you have dotnetfx35setup.exe