The issue seems to be that the current view has not been modified. The "Save as new view" button will only appear once changes have been made to the current view (e.g., applying filters, resizing columns, etc.). As shown in the second screenshot, there's a "*" symbol at the top of "All Opportunity *", indicating that changes have been made to the view.
Try applying any filter or resizing a column in the current view, and you should see the "Save as new View" button.
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