there is no set number for a landslide victory for the elecotral college, but a couple sites I saw said for the electoral college it's getting 70% or 375.
but you don't need a set number to realize that Trumps approx. 300 Electoral votes is not an OVERWHELMING victory - which is what defines landslide. it's just common sense.
amongst Trump's transgressions, you are right, it is trivial. He has lied or exaggerated far far worse things and many times also. Regardless, I'm just pointing out his obvious exaggeration here and you find it important enough to keep defending.