I updated the 3 sites I manage yesterday to 5.57.0. One is a D7 site and two are WP. Now on all of them, if I use SearchKit and then "Action > Update" the window to do the action does not pop-up. It is the same if I use SearchKit for contacts or contributions and again, it is happening on all 3 site. I am even seeing the same issue on the sandbox site: https://dmaster.demo.civicrm.org/
Will be fixed in 5.57.1, or it's a simple patch you can make.