There should be some sort of artifact (I would say getting from an NPC drop would be the best) that you can use on your ship that makes enemy ships unable to debuff you for say, 24 hours?

I thinking calming amp does that.
If it does, I think it's more than sufficient. Only time I care about debuff would be when I'm doing stuff, during which time I can keep CA on.

If it doesn't.... make it so it does?

a calming amp is kind of like a halc, you can only use it if you have no offensive actions in the last 24 hours. Well during a war or times of trouble you want to be able to attack, but its very annoying when anyone can just arti spam you and get your defense down to basically nothing and disable you.

Arti spam is a perfectly acceptable method of war.
Frankly, I don't believe you should be able to immune to those if you are performing offensive action.
So if that's the reason you are asking for this, I would have to say -1

If it only prevented npc debuffs i would say +1 but currently debuffs on pvp are a tactic to use even if spaming them is frowned on.

for those we have containment cages which are sendable unlike null fuses.

This suggestion was about debuffs which you can also use cages for....

wasnt Mwchism asking for an NPC drop that stops arti spamming?

Cages can be sent, missiles cant be.

The only reason why i mentioned the npc debuffs is because for "having a chance" to be inflicted that chance looks to be as high as 75% or higher at times

I just think its dumb that anyone can arti spam you and get you down to no attack and no defense, so if youre offline youre basically helpless. Whats the point of having a strong ship if anyone can just use artis and make it weak?

The price they pay (mostly in energy) to disable you. After all, no matter how strong your ship is, with debuffs or not, it is just a matter of having enough energy to get the disable.