Hello and welcome. There is much to learn. If you already have the basics and have free time, I recommend that you fly with experienced people. Then you will see that you advance in your learning much faster.
People always talk about the dynamic campaign. Although the determining factor goes further. For me it’s the user interface that allows you to create flight packages and modify target waypoints and loadout very easily.
In multiplayer. My squadron flies every afternoon and a single mission is done with a good birefing and debriefing. Not the pew pew of dcs and il2 (yes I know that cooperative campaigns are done but it is not the usual).
The most impressive are the communications and of course the most important point that no other simulator could match: the incredible artificial intelligence.