How to activate the chart/object next to a button?

I have a dashboard with multiple pivot charts. A macro controls chart formatting based on numerous criteria. The dataset is huge and frequently changes, so I want to update manually, as needed, on a per-chart basis rather than running on Worksheet_Calculate/_PivotTableUpdate/_PivotTableAfterValueChange/etc. (which would make everything intolerably slow).

The current macro iterates over ActiveChart, so I have to manually activate each chart before clicking the button. My question is: How can I activate the chart above/below/adjacent to the clicked button? I realize that I can make a separate macro for each chart that first activates the chart and then calls the main macro, but I'd much rather just have one script that can figure out the chart of interest based on the button location so it dynamically adapts to new charts/moved charts/changing chart names.

Sub UpdateChartAboveClickedButton ()

    Dim wb as Workbook
    Dim sht As Worksheet
    Dim btn_clicked As String
    Dim btn_location As Range
    Dim cht_to_update As ChartObject


    Set wb = myworkbook
    Set sht = wb.myworksheet

    btn_clicked = Application.Caller                                'find clicked button
    btn_location = sht.Shapes(btn_clicked).TopLeftCell.Address      'locate clicked button



    ---------------------------------------
    cht_to_update = ???                                             'find chart object directly above the clicked button
    ----------------------------------------



    With cht_to_update 
        With .Format
           [code...]
        End With
    End With

End Sub

(Also, if there's a better option than using the ApplicationCaller's .Address property, please say so. It was just the most straightforward thing that popped to mind.)