I added axios when I made a small CRA app, it was the only thing I was tempted to add. The kind of people who just wrote their 12th blog post about how "I finally understand monads this time" might want redux; if I had any question about how to handle states v. props I might add mobx.

I need a CSS framework like I need a brain tumor. With CSS you can learn CSS and make a web site look like you want. With bootstrap you can learn CSS and learn bootstrap and almost make a web site look like you want.