I like that the company which takes users' privacy interests seriously exists, and I am more than willing to pay for it. Unfortunately, they don't have their own search engine and social network.
For social, well I use twitter and simply don't provide extra details like date of birth etc, but it probably depends what your goal is with a social network?
DuckDuckGo isn't that good. I would use Google and sacrifice privacy.
Concerning twitter, IMO, it's no different than others. For example, they still use social button which theoretically might collect information about the sites you visit.
DDG is obviously not as good as Google, but I've given it a serious try and it works well enough. There are still times when I instinctively add !g to my query and times when I know that I need to use Google instead (some work related stuff just doesn't come up on DDG)
I can't speak for any social networks since I don't know how to use them which means I get no value from them. I mainly use IRC and lately Discord to speak with my friends.
Which is valid opinion. I just view it like if you are going to spend the money on iPhone and still use Google's services you are "losing money". You could have just gotten Android which has better Google integration for cheaper price.