Detected as a virus and automatically removed by Windows 11
I had the same issue. I don't have a good solution, since I just went to Linux and used the Legacy-iOS-Kit to sideload socket. Is it possible to get Defender to ignore files like other anti-virus solutions?
I was able to make an exclusion for socket. Open the Defender app and then "Virus and Threat protection" > "Virus and Threat Protection Settings: Manage Settings" > Scroll down to "Exclusions". I first made a blanket exclusion for the Downloads directory. Downloaded the IPA and then made a specific exclusion for that file. I was able to upload it to my iPad with Sideloadly.
Note that I do not recommend leaving this exclusion in place unless you move the file to a read-only location.