Thank you for your answer. I was already aware of these Simple apps, but they doesn't suit my needs since they are not as elegant as the Material You one.
Does AOSP apps are going to get a redesign (in the future by AOSP community or maybe GrapheneOS team)?
Until this happen (or not), do you think I can replace Contacts with the Google one? (Network off, but is the app still able to communicate with others like Google Play and then leak my contacts?)
Sorry if I wasn't precise enough, I am not a native speaker.