The pose itself would be more appropriate for you with the pelvis tiled forward. I can’t tell if you’re on something there already. If you are not, then I suggest sitting on a folded blanket. With the sitting bones just on the front edge so the pelvis tips.
Generally speaking it is not the pose which does this or that. It is the actions within the pose. Two students could both sit perfectly in that posture relying solely on openness in the muscles to do so. One might be working like the dickens internally while the other is just flopping open.
Flopping into poses is “nice” but it’s not particularly “Yoga” and for those people open enough to flop it’s not particularly stretching nor is there much in the way of musculo-skeletal integrity.
Baddha Konasana, with the proper actions would likely do more for your flexibility than gravity would in this pose.
But flexibility, in and of itself, is not Yoga. However some range of movement is critical (what range we can debate all day). That sort of exploration comes through a robust practice. Not one pose. I don’t want others to get the idea that “Sukhasana increases flexibility”.