To clarify: this question is about posting on meta sites.
To share knowledge, it is recommended to post instant self answer. However, what do you do if the knowledge isn't an obvious answer to a question?
I see the following options:
Post the knowledge and ignore the question-answer format. This is the simplest option, but it has the downside of not corresponding to the post format of the rest of the site. Nevertheless, this is what I usually see when people posts statistics/graphs. I did it myself here, and another good example is this.
Post the knowledge as an answer to an arbitrary question. To fit the question-answer format, people often try to create a question whose answer will fit their knowledge. However, not all knowledge easily fit the Q&N format, so this solution often leads to vague closed questions such as this one.
Post the knowledge with a side question. This solution would be the same as the first, but adding a simple discussion-promoting side question to fit the Q&N style, as done here. This would follow the format of being a question, but likely not promote any good answers as there is no good question.
Don't post the knowledge at all. Acknowledge defeat. After all, this is a question-answer site.
All of the methods have downsides to them, so I am not sure which one to use. Is it always recommended to use self-answers, even if the question might be extremely vague? Or is it better to ignore the Q&A style?