I have recently (today) ranked up and let me tell you this, 'Forget about merits' and find your interest area in which you are passionate. Engagement will occur naturally if you have some things to share.
If you cannot tell your interest area then you have to give yourself some time, relax, and enjoy parts of the forum that are relatable to you. Yes, it will take time, there is no way around it but soon you will realize it is a process not a state.

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Congratulations on ranking up. I know that feeling of having the approval of being worthy of ranking up.

What you said about how natural engagement comes and how one can earn merits without even trying to get some is what most newbies don't understand, even though it's a very simple thing. If we look at our lives in general, we tend to fail the most when we try very hard to achieve something because we are mostly focused on winning instead of focusing on what we are doing and whether we are doing it right or not.
When you have a goal, you have to think about possible ways of achieving that goal instead of thinking about success all the time and being more focused on winning than how you can win. So, the moral of the story is that our focus should be on what we are doing so that we can do it efficiently. Eventually, the target will be achieved if we master it.