walraevens If this is not a plot twist you're trying to hide and shock readers with then go on and use it. Don't introduce too many characters or events in your synopsis, focus on key elements that are easy to grasp by reading your novel's 1-5 chapters and yet are interesting and may catch someone's attention right away. If you're writing a story with a 'cheat' or 'op system' that are available from the start and interesting them I would focus on introducing them in a funny/intriguing way. If you're writing a love story where the girl plays the part of a prince maybe your synopsis can introduce that character like a guy only to mention at the end something like 'If only she was a boy' etc.
As for posting on watapad ... give up. New stories don't have any exposure over there and drown in millions of others, you will get like one reader per month.
As for RoyalRoad that's a good idea, people over there are active, like to comment, the site gives you many tools that author's like (exact count of views per each chapter etc.) the exposure is fair and it's easy to gather some additional readers, but they tend to be a bit favorizing towards the litRPG genre and similar.