Haha fair, Warframe has a lot of jank, especially on all the older side content like archwing.
I think the mission you're having trouble with is the pursuit, if I remember right you have to shoot the engines first to slow the ship down, then shoot little round shield generator things. Was that mission required for progress? If not, you could come back to it later with better guns. I think Grattler is the first AOE archgun you can usually get, the blueprint for it comes from clan chem lab, so you would have to join one (or create your own and research it).
Also if you want help, you can add me (GaerthGL in game handle), I'll be happy to help if we happen to be logged in at the same time.