Currently, for all Add-ins other than Excel, the https://learn.microsoft.com/en-us/javascript/api/office/office.ribbon?view=common-js&preserve-view=true#office-office-ribbon-requestupdate-member(1) method takes in a https://learn.microsoft.com/en-us/javascript/api/office/office.ribbonupdaterdata object that only allows https://learn.microsoft.com/en-us/office/dev/add-ins/design/disable-add-in-commands for Add-in controls. However, even for Excel Add-ins, there is no option to dynamically update the label of a https://learn.microsoft.com/en-us/javascript/api/office/office.control, or the option to make a control/command visible or invisible, similar to the tab visibility option for https://learn.microsoft.com/en-us/office/dev/add-ins/design/contextual-tabs.
We need PowerPoint Web Add-ins to be able to update the label of a control programmatically, after the button has been rendered in the Ribbon. Alternatively, we need the option to change the visibility of a button/control.