Not gonna make it any more effective with how heavy it is. A rapier like Myrtenaster (or is it a rapier? I'm not entirely sure what that type of sword is called...) is designed for stabbing, whereas longswords are simply not.
I think the problem isn't so much that the group can kill it, the problem is that the ogre is super tough at face value but also fairly easy to defeat with strategy. Then again, Blake can't really do shit about it because of how Gamble Shroud works, and I don't believe Asta's swords are up to the task beyond defense. Weiss, meanwhile, has a piercing weapon and her glyphs. It's still going to be a fun fight, but with how the Ogre is described, it's either going to be balls-hard or a cakewalk unless the ogre plays defensive and the team is forced to put strategy into play.I regret bringing the ogre in, I wanted to give you all a cool boss fight, but Asta and the group can kill it in mere seconds because they're anime characters.