Is iOS AdGuard secure?

I am looking for an iOS ad block and tracking block and anonymity app. I don't know which is the best. So please tell me! Being open source is essential. I found AdGuard Pro, is this the best?

AdGuard is a reputable company and we list their DNS. Not sure what you mean by secure though. I’d assume their iOS uses HTTPS for all network requests.

I also use AdGuard on my device. I am only free user.