The blade feels wobbly and moves when I swing the saber

For most sabers, using only 1 retention screw solves this issue. You can also add .5 to 1 layer of electrical tape to the base of the blade to make it slightly thicker, and use 2 retention screws, especially on the “thin neck” models like Luke ROTJ, Obi Wan EP3/4 or General Leia.