It's not exactly like that, considering is the mind of Lucemon in well...fucking Ogudomon X and Alphamon didn't battle him but is explicit that Ogudomon is superior to Chronicle X Alphamon. So yes Lucemon solos and if we using a composite he has the god factor as well and thanks to that he didn't have concept of damage.There was a version of Lucemon semi-recently that was shitting on ALL the Royal Knights (yes INCLUDING Alphamon) and was only defeated by Jesmon GX.
Long story short, Composite Lucemon solos anything DB related.