My office mate is a beard fanatic, and has a beard that goes past his belt buckle. He doesn't wear it loose at work. It does taper to more wispy at the ends, but there is still quite a bit of it. For work, he neatens it up by rolling it up, and tucking it in, pinned with a couple long bobby pins, so that it is close to his face, and very full/solid looking. The sort of mask that has folds to let it expand can be made a bit longer to curve around a tucked up beard.

It does seem sensible that there should be mask patterns for masks with a sort of snood to hold a beard out of the way.

Joanne in Cleveland, still figuring out how to make a mask that fits me comfortably