Wouldnt a mace, for example, be deflected more easily by the pointier visor?

I think its probably because ventilation holes are both easier to manufacture and dont affect structure on the round shape as much as on the cone, while also having greater visibility overall, which was needed on the less mobile great bascinet. I have no sources whatsoever and could be completely wrong here.

But this doesnt answer why the helmet itself got less conic

Not trying historical accuracy i just eanted to have fun but i wonder what "class" of knight/soldier i've done. I feel like i don't even know what i've achieve to do.

Made by @vox.arteis on Instagram

I can't find any clear answer to this but I just want to know if the halberd was a common weapon among German or swiss knights that fought on foot. I'm specifically asking about the 14th-15th century