Count marks

My first attempt would be to abuse chord symbols (or possibly sticking) text for this. As both are entered on a given beat rather than on a given note/rest.

In theory staff text can also be attached to any beat, but in practice it can be harder to get that effect than by using chord symbols. But - I’d actually suggest using Roman numeral analysis (see Add / Text) instead. Just like chord symbols, it allows easy entry on any beat (eg, press “;” to move to next beat), but it won’t try to do special parsing of what you type - it gives you more what you asked for. You’d just want to change the default font from Campania to something else (because that will superscript most numbers), also change placement from below to above. So make the change in the Inspector then hit the “Set as style” button.