Hi,
You can try using separate calendars ("Extra Calendars') to mimic categories across PC and Android since Android doesn’t support categories directly. To quickly manage which calendars are visible, Outlook on PC allows you to check or uncheck each calendar in the calendar list, but there isn’t a built-in "Select All/None" button, however, you can speed this up by right-clicking a calendar group and choosing “Show/Hide All Calendars” if your calendars are grouped, or by collapsing groups to hide multiple calendars at once. On Android, you can toggle each calendar individually in the calendar view, but again, there’s no native select all/none option, so grouping calendars consistently on PC first helps manage them more efficiently on both devices.
Kind regards,