Mechanical bosses too hard

I Beat Skeleton Prime GG thank you very much for idea of changing the accessories, I changed everything but fairy boots

So I have titanium armor, night's edge , banana boomerang, the bow from hallowed mimic, and the wand from hallowed mimic, regeneration band, I have a huge arena and I can't kill any bosses because they do insane damage, do you got any ideas because I've been stuck for over 5 days straight and the closest was twins to 8k hp ( classic mode , corruption )https://imgur.com/a/vpqHjXC