You're asking a 'what is your opinion' question. There's no right answer. And you're not likely to get an objective opinion in a community forum run by Microsoft. But here are some facts that may help you.
1- Windows Security and Microsoft Defender are separate products.
2- Neither one includes McAfee or any other third-party application.
3- Although on any given day, antivirus "A" may be better than antivirus "B" in independent testing, on average, most antivirus applications are equally effective at what they do.
4- Nobody knows Windows like Microsoft. However, nobody knows about viruses any better than anyone else.
5- Viruses are only one of the many threats coming in from the internet.
6- No one can rely on software to protect them on the internet. Most threats coming in from the internet today have learned to avoid antivirus software.
7- No security software can protect you against data breaches.
8- Study after study shows that, by far, most attacks from the internet succeed because users were tricked. Learning how to not fall for tricks will protect you much better than antivirus software.
9- In addition to whatever steps you take to protect yourself from attack, it's important to maintain the highest level of security for your PC. Believe it or not, there are people here who try to remove their computer's password protection and take other steps to weaken their computer's security.
So how then do you decide on which security software to use, if they're all pretty much equally effective? Look at other factors, like: Which product makes sense to you? Which do you find easiest to understand? Which company provides better support? Which product interferes the least with how you typically use your computer? These are things you should be taking into consideration.
For well-informed and independent opinions, I suggest reading the professional websites, like PC Magazine, CNet, PC World and others. (And avoid "what's up YouTube?")