No there isn't. Have you tried a sleeping bag?
Mine did it even in her sleeping bag but she's working out the bounds of her cot and does it less and less
Nothing that attaches to the crib is safe. A sleep sack is your best bet! It really doesn’t take long for them to learn the boundaries of their sleep space.
Purflo breathable mesh sides
They will get used to it
I’ve no idea on the safety of this but could you cover the outside of the bars with mesh?