The gluteus medius muscle helps move the hip joint. It also helps stabilize the pelvis when walking or standing, so when it’s weak, it can affect the way we walk. These exercises should help retrain & strengthen the gluteus medius.
Starting off on your side, modified side planks, hip abduction, clamshells, and reverse clamshells are a great way to help strengthen the glute muscles.
If those become easy, planks and planks with a leg lift (or leg extension) are great as well.