For me Windows Defender is not enough to secure your system against all kind of threats. Coz if you experience installing any kind of Internet security or anti virus, you will find out na some of leading antivirus and internet security will block any suspicious links, website, application, hidden runing apps that may harm your system na hindi mo ma experience when using the windows security.
For me i recommend to use ESET Internet Security if you are a techy person and will find ways on how to secure your system using you IT/Tech skills. If may money ka naman go to other internet security or antivirus such as Kasperky, Bit Defender.