knowledge of any wrongdoing. His testimony is filled with leading questions that he answers with 'I heard...', 'I believe ..." he never answers that he had direct knowledge of anything.
Another civics lesson for you.
Ambassadors do not set foreign policy. If he did not agree with the foreign policy of the President then the honorable solution would have been for him to resign his post. Career swamp rats to not set policy, they implement the policies of the duly elected officeholders.
Here, read his testimony yourself.
https://www.documentcloud.org/documents/6540356-Sondland-Transcript.html?embed=true&responsive=false&sidebar=false