The simplest answer is that it's entirely up to you. This question is asked regularly here and you might find some good example workflows by searching the forum.
Some folks do isolate social media apps to their own profile, others mix and mingle. Some reserve the owner profile strictly for making system changes, using a second profile as their primary, etc.
I use the owner profile as my main and do not use proprietary social media apps on the whole.
As for app management, I believe the official stance is that the Google Play Store is recommended for most users as a secure and convenient method of managing apps; followed closely by the Aurora Store for those who desire anonymity. Finally, directly downloading the APKs from app developers (e.g., via Github releases) seems to be preferred over the use of Droid-ify and F-droid.