Not sure, working for me rn, but you could try downloading .net manually from Microsoft https://www.microsoft.com/en-gb/download/details.aspx?id=21

i unfortunly had this issue and the only way was to fix it by downloading windows 11 or what ever windows it is off microsofts site and reinstalling it to fix the error that kept coming when ever it tried to install or enable net 3.5 there is also some other fixs pacificly for windows 10 when you goggle the error that idk if they work or not