Not upset about auto-fire + Jury Rigged combo, since as a GM I can throw down opposition that's far worse and turn the PC into a greasy smear if I so choose. But then I'm lucky that I don't have players that are power-gaming munchkins who'd try to abuse the system that way in the first place.
And given how you're trying to twist the system to exploit it for maximum mechanical benefit... that's classic munchkin power-gaming to a T.
But hey, if you want to go have your lonely fun trying to build the perfect weapon or perfect armor to the exclusion of all else, go right ahead. Any player that tried that at my table would be told to stay home and have fun rolling dice all by their lonesome while the rest of us enjoy a fun adventure where the PCs actually accomplish something of merit.
As Krieger22 said, Planet "Hypothetical Ultimate Best Case Scenario" isn't the planet we live on.
Ironically how you call me a munchkin power gamer and going on that to a perfect example of those gruesome railroading GMs who want to have their pcs actually accomplish something of merit. We seem to be from different planets indeed, I reside on a character driven systems while you seem to come from a d&d train which lines the PC up to follow the lead to accomplish the goals of the textbook adventure. SCNR. I bet that impression I have is just as wrong as yours, but we seem to be really from different planets.
Acquiring the tools, materials and the knowledge alone can be a whole adventure, and as I said, PC time is anyway limited, so speaking of whole session of just rolls sounds like a quite crude interpretation of crafting in RPGs in general. Degrading it to just throwing rolls sounds like degrading combat or social encounters to just rolls. Speaking of that, Chronicles of the Gatekeeper sounds like at its core it is a adventure about acquiring materials for a crafting roll. ;-)
But the point you so clearly missed in your hurry to be "right" is that while as I GM I "could" do those things, the simply matter is that I DON'T.
But you've long since proven here and in multiple other that you're not really worth trying to have a conversation with, as you can't begin to comprehend the notion that you might not be 100% in the right, so go ahead and do whatever floats your little boat.
*adds to Ignore list*
I feel like I should deeply apologise for not mentioning that I am not always right. And that water is usually wet. Well, on earth at least, outside of polar regions. What else? Hmmm, a yeah, I apologize as well for not mentioning that every group should handle and adjust their game like it suits them … I could go on and on with stuff that I really should have mentioned. I apologize. And to be honest, I am grateful for the plonk, because I much rather talk to people who do not get offended when someone does not mentions the obvious.
Speaking of stuff that should go without saying and seems not to go without saying:
A thing that I personally don't get why a lot of players seem to focus and FFGSWRPG as a narrative system when the system still use dice and their interpretation as the huge source to drive that narration and comes with all those tropes of DnD, including silly stuff like + One Advantage Screwdrivers of Success together with a million tables for crits, spending advantages for literally everything and anything, depending on what you do, where you do it, when you do with, with whom you do it. Tables for everything to tell you what your actions "can do", a thousand items with small extra dice for everything, from "Owners starship manual" which grants you an downgrade of difficulty on mechanics checks, to a personalized toolkit which grants you a bonus die, but everyone else a setback to travel guides which again grant you bonus dice … the complete mechanical side of the game is the straight opposite of a narrative driven RPG. Very equipment driven, very gamey, with a lot of DnD and CRPG vibes in the whole mechanical side of the game. The main narrative element in the system is not telling the story of your characters, but the story of their dice rolls and you roll for quite a lot really.
So another suggestion outside of those gamey mechanics: Just work with your GM and develop that template for a weapon with breach directly yourself, ignore happily the given templates and just develop your own template and integrate it into your game. Just as Uthanono said. This is really the easiest solution, just house rules, creativity and a dash of creating your own game. It's really not hard and even if your template turns out problematic at a later date this can always solved simply narratively and as well mechanically by discovering new draw backs or tuning down the weapon. The first one is a prototype after all and those are well known for developing their own quirks, bugs, problems and side-effects.
One thing to note when developing such a weapon: The main reasons why lightsabers have breach is the power that a kyber crystal gives that weapon. Finding such a crystal is an adventure on its own usually, but those crystals are indeed not exclusively used for lightsabers. The deathstar for example used a giant kyber crystal for its superlaser and just hitting that giant crystal with a blaster would amply the blaster energy by magnitudes. (Crystal Crisis on Utapau)
There are more conventional weapon like TFA era turbolasers which use as well those very rare crystals to enhance performance of the weapon, so something in blaster form might be possible. ( http://www.starwars.com/databank/finalizer )
Hmm, we've got one spare kyber crystal in a useless holocron …, but that is off-topic ;-)