I have had two types of gutter guards. One was a circular type of brush and the other a plastic grid that clipped onto the top of the gutters. Nether worked as they both got clogged with leaves and even harder to clean, so they were both removed. Also tried down pipe filters, again all that happens is they block up with compacted leaves and rain over spills the gutter as the water can't get into the down pipes.
Think the answer is a very large chainsaw!