How do I add new artifacts?

I didn't quite understand... Did you always change only 3 artifacts? Or did you duplicate them and could create as many as you wanted?
The thing is that the list of artifacts in Armageddon's Blade is quite large.

Usually, I needed one or two scenario artifacts, and I would change the existing ones at my discretion. But as long as there is an "Add" button in the parameters tab, I think it is possible to add a large number of new artifacts; unfortunately, I don't know the upper limit. I only added my own artifact once, just for fun. I haven't tried checking it with GSComp, but when I accessed it through scripts using the ID (ARTEFACT_SPEAR_OF_ETERNITY)... it added that artifact! That's why I decided that this method might help you.