The MORryde STP57-024 Replacement Leg is a suitable solution for the pitching issue experienced with the current step leg on your 2019 Flagstaff Micro Lite 21FBRS. It is designed to provide better stability and usability, helping prevent the stairs from pitching forward and reducing strain. This replacement leg supports up to 500 lbs and weighs approximately 7 lbs. To ensure proper fitment, close-up photos of the mounting points and a side view of the full step assembly are recommended. You can order the MORryde STP57-024 from Elkhart RV Parts, and if you need further confirmation or assistance with installation, the Elkhart RV Parts team is available to help.