Every Congressional Office will have a slightly different set of deadlines, often a week or two before the Appropriations Committee deadlines.
The Cincinnati Business Courier reports on March 7, 2023 that Rep. Greg Landsman (D-OH-1) is now receiving requests through his Congressional Website. The deadlines for requests is 5pm EST on Friday, March 17, 2023.
Make sure to check the Website of your Member of Congress to find their specific process and deadlines.