A stationary/static lunge is a very powerful exercise to strengthen your legs, lower body, and core. It does not have to be super difficult. It can be a low lunge, high lunge, or you may start with a half kneel if the other two are not possible. Feel a lift from your pelvic floor and pull your core/belly in during this position.
Do NOT collapse into the position, instead, rise against gravity. Imagine that both inner thighs are moving towards each other.