2 videos out of sync
55.58 is not a standard frame rate so it's the one that should be changed. Using the 23.98 video as a reference, pick a point late into the video where you can determine how many frames (at 23.98 fps) it's out of sync with the 56 fps video. Compute the ratio of the length in frames up to that point, to the number of frames out of sync. Then time stretch the entire 56 fps video --  either shorter of longer as needed -- using that ratio.