I don't know why I didn't think to use a sword. I'm sure that's what I've done before :/. It's not like I don't use picks to get efficiency etc etc :/
Thanks for the kick in the pants to shake my brain loose
So I've now lost 5 sets of armor/jet pack/sword/crossbow trying to kill the chaos guardian :/
However I'm now up to 69 attack on the crossbow.
I've lost one set of wyvern and one set of Draconic then a bunch of useless flux armor etc. I've also lost the mystcraft platform I made for a quick escape.
I'm going to give up till I get some more dragon hearts from summoned dragons and can make another full set of Draconic armor, just need some souls. With the crossbow I'm making now I can take it out quick. Trick is to get it away from the island. Then you don't need to break crystals.
As I've said elsewhere, you think the Draconic stuff is OP until one hit from a guardian takes out an entire level of yellow hearts.