In my opinion, there's a difference between quality post and merited posts. If you ask for what quality posys are, I can't give a definite answer since the forum didn't define what quality posts are.
Quality can not be used to quantify a post it either a post is good or bad, there is nothing like a quality post, the whole merits thing, is just how people react in their way since we do not have the React and Likes button merits is the only way people react, I have seen some low post being merited and somewhat seems to be a good post being ignored.
I just want to add about quality posts and appropriate posts. Quality posts are certainly posts that have many benefits and attract members to start discussing and giving their opinions. A quality post is not just a forgotten post, but a meaningful post that discusses several problems and the various solutions provided. that's the purpose of why you have to post quality. Post quality rules are not explained in detail.
As for the appropriate post, it is a post that deserves to be discussed and is correct in grammar and writing as well as the content of the post that does not offend anyone. Inappropriate posts will not be accepted and will be deleted by moderators because they are considered SPAM.