There is no rule against this, however most deck discussion for events like this are done in unaffiliated communities or in team chat. The functionality of the forum and low traffic on the appropriate subforums make it difficult to have meaningful deck building discussions — they are generally better in real time.
I would be happy to send you a link to TP9’s public Discord, I know there are also helpful, public communities in Slack and on Reddit that @Sarahschmara would be happy to point you to if you are interested.