You are not alone, but this is a very complicated thing. People seeking support are not the ones who will read rules, fill questionnaires properly, etc.
https://stackoverflow.blog/2010/10/04/asking-better-questions/
You can add a topic template to your support category, but some (or most) users will just ignore it.
If you must have structured questionnaires and can’t live without it, you may want to use a different software as Discourse is geared towards free form text.