Change the OnClick action from Save Changes to Call a microflow. In that microflow add an activity for Save Changes and you can then both save changes and carry on with the other actions you want to add.
Don’t forget to add a close page activity if you’re calling from a popup window.
The standard Savebutton only does the save. Remove this Savebutton and add an Action Button that starts a microflow which takes as input-parameter of type (list of) entity that you want to save. The first activity in the microflow can be Commit for the input-parameter