I have a mare with a killer bascule with a kick behind (love her tail flip). As a result, I leave the bigger jumps to our trainer.
Her mother, who I competed in lower level eventing, was the same way. Not easy to stay with.
I agree with others that your saddle looks a little small. Just sitting in it may feel and look correct; however, it can make a difference and actually “push” you loose. When I was saddle shopping, every saddle at the tack shops put me in a 16.5 and technically, it did fit me. I decided to look/sit in saddle when I was a Rolex so I could see them all. My top pick at the time was Amerigo. I was fortunate to have Peter Menet, the saddle designer, fit me. I sat in the 16.5 and he agreed that it “fit”, but when jumping, I would not be happy with it. He put me in a 17. It all had to do with where the beginning of the cantle met the upper part of my leg. Because it met too high on my leg, it would push me out of the saddle when jumping. So, got back home and tried both 16.5 and 17 - he was absolutely correct. Didn’t mean to make this an essay, but for me and a big jumping mare, it made a difference in my ability to stay with her.
All the other suggestions about position and release are good recommendations. It is all a learning process. Love your horse, BTW.