If things worked the way youre trying to argue then the beginning of this movie the Rebellion would have turned 5 or 6 xwings around, flown them into the First Orders ships and the movie would have ended because in our real universe something going that fast would have enough force to take those ships out. I think its pretty obvious that we can officially establish thats not how it works. I dont think snokes ship would have been cut in half if this were the case, it would have been obliterated.

You are imagining a world where every idea is 100% flawless and doesnt take research time, building time, etc.. But the world doesnt work like that. And Star Wars doesnt either.

What your missing is why would anyone have any need for this type of ship.

If no one needs this particular thing, it is not going to get developed. Your argument about the Rebellion losing ships just proves how much you dont actually understand this concept. The Rebellion didnt develop xwings. TLJ even shows they buy ships off the black market. You cant buy a ship that doesnt exist. Why would this type of ship even exist? What purpose would it serve that would be useful enough for it to get developed and distributed? None. At all.

It doesnt matter how casual a Star Wars fan you are, a simple concept you dont understand is that ships move slightly over the course of battle! Its not just the fighters that are dodging and weaving, the small ships and capital ships change positions too. If your 100% automated kamikaze ship arrives at a scene and none of the ships are in EXACTLY the same place because that what it would require, its just a floating piece of junk. Someone has to be on board to tell the ship what to fly into. Even if it arrives at the same time this ship has to be told what to do and when. This is not hard.