Because NBT is very limited/not possible in Bedrock edition, and many questions pop up regarding Bedrock Edition NBT (such as this), should we create a duplicate target/recommended closure flag for these types of questions?
I seriously think that this is an unnecessary shortcut.
Now because you haven't reached the magical mark of 3000 rep for voting to close, I'll give you a sneak peek into how the system works, and show you why I have the opinion I do.
When selecting "Duplicate" in the VTCshort for Vote to Close dialog, you must select which question to mark as duplicate. You can search for a question yourself or enter its ID number, but also, the dialog presents you with quick options you can select. These quick options are based on how many duplicates point to that question, as well as related keywords in the question title/body, and ones with similar tags.
Now I searched the following search on Arqade:
[minecraft-commands] or [minecraft-bedrock-edition] -[minecraft-java-edition]. Then I selected the first five questions that were not yet closed, opened their VTC dialog, and looked at the quick options provided.
All of the five questions that I found had the main BE NBT question in their top five list. Therefore, I believe that an option "Duplicate of BE NBT question" is an unnecessary shortcut to take, as the question will probably have it at or near the top of its list.
And if you are skeptical of the ability of the quick-options to present you with the BE NBT question when it's needed, you can just memorize its six-digit number (which is 334102) and type it into the VTC box when prompted. When you get very experienced, this number should become just as easy to recall as the bug report ID of the famous quasi-connectivity bug report.