I will say that 3H probably isn't quite as strong as presented- like, there's
legends of the Sword of the Creator being mountain-cutting, but we never ever ever see it do anything close to that (and a lot of the info on Relics is outright lies)- Byleth never cuts even a small hill in the cutscenes in any route, and even Nemesis-in-his-prime (from the
opening flashback cutscene) can kill couple dozen people with each swing, but he isn't wiping out entire armies or alter the battlefield's terrain or w/e. Similarly, the Javelins of Light are not really nukes. We get a
goodish look at their aftermath in VW+SS, and they're more like powerful standard missiles than nukes- medieval buildings that take directish hits are gone, as are the buildings next to the target, but the buildings two or three away from impact are damaged but not destroyed.
The only Javelin aftermath that is really nuclear in scope is Ailell, and there were some...special circumstances involved there.