I'll still point out that it could easily murder our Pyra teammate when theyy focused on him.
Yes 1on2 tri art junker does suck like any other build in 1on2. when you have another 3art junker backing you up. Assuming both junkers have enough time to dissable you you don't stand a chance. Spire, junker,goldfish and galleon are pretty much out against artemis gun line- unless you have guners that can reliably hit outside artemis range with merc, LJ and h.Flak spam.
Mobula IS a reasonable-to-good counter since the guns are spread out and engines are outside artemis line of sight from front, mobula has best vertical mobility (witch is waht you need agains armenis with severely limited upward arc of fire - heck going up with a pyramidion saved us from 3art junker against Mad Hatters a couple of weeks ago when our frond and engines were dissabled).
I do think Artemis is OP, but very little (i would a: increase maximum upwards angle by 5° decrease horizontal arc by 5°bo both sides, decrease AoE size and damage no more than 10%, and then I think it would be just fine - or b: more heavily penalise direct hit explosive damage component [up to 50%] keep same shatter damage on aoe component, and keeo pther changes the same as in option a)
EDIT: Squid Mobula against double max artemis junker could work well too. Spitting your ship verticaly so they come at diffirent heighs, so junkers cant switch targets immediately, should help. It's waht we used aginst entranched artemis gun line on fjords.