@sanatisharif it's easier to recreate the post in the new topic than creating a plugin for it.
and there is no point in creating multiple topics for the same thing. The answer is NO. There is no plugin that merges topics and the functionality is not available in core.
In fact, I talk about upgrading the database design of nodebb forum, for the next version, do not get me wrong.
I showed a little issue to introduce a major weakness. so we can improve nodebb database design.
The strength of the current design is that, now you can easily move topics,
because in practice there are no dependencies between topics and categories.
(Each category is just a container for topics, nothing more)
I think this policy should be applied to posts and topics, in which case you can apply any changes on posts and topics easily.
so you have better design, tell me if i'm wrong!