My worksheet contains button (form control/ActiveX) but SharePoint Online/Excel Web Access does not display it. The button just mainly print another worksheet (printer-friendly version). Is there another way of accomplishing this without needing to open Excel?
Controls are unsupported in Excel Online. You need to open it in Excel.
Controls, such as ActiveX controls and form toolbar controls, prevent a workbook from being viewed in a browser window.
More information, you can refer to: Differences between using a workbook in the browser and in Excel