Sandals can be tricky for me as my ankles are so skinny. I've just bought a pair of chunky sandals and I like them, but they feel too big, even though they are my usual size. I've added an extra hole to the strap which has helped, but my foot is still slipping. I can't exchange as they are from vinted.
So is there anything I can try they will help, would an insole look OK in an open toe sandal like these (pic attached) I do really like them so it would be a shame to have to resell them. Paid a fraction of the price buying them off vinted and they are unworn.