All people who wish to help others:
Is a forum the best platform for this Arduino learning community or is there anything better instead of a forum?
In a forum, you post, others respond. You post again and others respond to you and other responders etc. It's really easy to lose focus what you have been told to do as an OP and I see this a lot in recent time. OP posts questions and others respond with questions of clarifications and suggestions. Then OP would ignore multiple requests/responses and move on to say other things, or just take a long time to provide any response.
I think this problem is the problem of a whole generation of younger people. I've been teaching them for 2 decades and things get worse in recent years. You ask them and they may respond to one out of several apparently important things you asked, such as in email. The exposure to social media may have caused their attention deficit disorder. It is especially hard because volunteer or professor (paid), we all do what we can to give advice and wish to see those younger people respond to our advice yet many if not most of the things we say get zero response. I have started to email my students only one question at a time in the hope they will read and respond. We need corrective actions because a generation that can't pay attention will not take responsibility because many don't even know what they are responsible of.
So maybe a forum isn't the right platform. If the OP is required to respond to EACH reply, then maybe they WILL read more carefully. That seems to be the case if you talk face-to-face. You can't just turn away from someone talking to you and ignore a large part of what they say and still expect them to continue to converse with you.
So is there any existing methods to provide such a challenge/response system on top of a forum? I know that a typical forum or an email system don't have such thing. I wonder, what it would look like if one of these threads were done face-to-face, with say 1 OP and 3 people trying to help, all in the same room. I bet each person will have to take turn to talk and whoever should respond should do so because everyone else is expecting a response.