Why can't people find my posts in X search?

First rule out the boring explanations: a very new post may not be indexed yet, a protected or deleted post will never appear, and from:handle only works with the exact handle. Then compare a logged-out search with your own view.

X Shadow Ban treats an empty search result as a fail only when the account's public timeline has at least three non-reply posts; otherwise it reports untestable, because a silent account is not evidence of suppression.