The leg problem could be how the saddle is built, the way the stirrups hang. Seat size could be too big, so you never can get “over” your feet.
I am constantly amazed at how BIG the seat is on saddles now, with slender, willowy children riding them! Few have less than a 16" seat. And it DOES affect their riding because they move so much in that space. My daughter rode my old saddle, 14" seat, was always in a good body postion with no work. She was ready for any request to her horse that might need a change in games or tests. She got compliments on her seat and a lot of ribbons in the Horsemanship classes.
Way “back in the day” when I first went saddle shopping for my new horse, they only offered saddles in 14", 14 1/2" and 15" seat sizes!! Littler sizes for kids were available, but anything bigger than 15" was going to be a custom order saddle.
So you might want to go “sit on” a lot of saddles at the tack store, in various sizes, to see what it takes to get you sitting up over your feet. Equitation picture you want is the same as English basic seat, Head, shoulders, hips and feet in a line vertically. It is NOT supposed to be hard to do, if your saddle will allow you to get in that postition. Spine is supposed to be straight, not rolling your hips up under you to sit on your back pockets. For guys with a bad fitting saddle, pocket seat position might be common as they try to get comfortable.
DO dismount standing straight up in the stirrup. Then step down IN CONTROL of your body and speed. Some of the worst wrecks happen with floppy shirt tails hanging up on the horn, or snagging your belt, lower sweater hem, or your BRA! Seen that happen a number of times!! Those riders ALWAYS were leaning, over the horn, over the seat, so clothes easily snagged on the horn. They did not dismount by standing straight up AWAY from the horn, to step down and off the equine in a smooth movement. I really don’t recommend kicking the stirrup free and sliding down, as seen among many English riders. Too easy to hang up on western saddle parts.