Anyone here can lodge this simple form and I'd encourage you to do so. Especially if you think this merger will substantially lesson competition and stifle innovation lodge a complaint: https://www.ftc.gov/enforcement/report-antitrust-violation
At a minimum, they will investigate this and make inquiries (typically within months) if they see a high volume of complaints.
See https://www.ftc.gov/advice-guidance/competition-guidance/gui... For more info on the relevant law :)