I was a little fast myself. The SectionPagesMenu = “main” doesn’t generate menu items for the pages (maybe it should) (it just makes the selecting the active page possible).
In general you can access the current page’s parameter, but a menu item isn’t connected to a page, so I don’t think there is a easy way to get to a menu item’s page’s parameter … Which is what you want, I guess. If you look at Hugo’s doc site’s menu, you may be inspired to do this in another way.