Hello,
Try the DISM method mentioned here to enable .NET Framework 3.5:
https://www.kapilarya.com/how-to-enable-net-fra...
Let us know if this helps!
Note: This is a non-Microsoft website. The page appears to be providing accurate, safe information. Watch out for ads on the site that may advertise products frequently classified as a PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the site before you decide to download and install it.