and make it about 50,000 times more powerful
I've taken this quote out of its particular context, since it seems to be your general strategy for combating the Shivans. You don't seem to be considering the production costs- or even feasibility or physical possibility- of doing that for a certain weapon.
Let's take this thermite that you seem to be so obsessed with.
The Sathanas is 6KM long, and quite massive. Let's forget about the Dante and even the other 100 Sathanas juggs for a moment. How would you destroy one Sath with thermite? You can't just shoot it into the hull- if that were effective, the above-nuclear-grade Helios bombs would have pulverized the destroyer.
By all rights, a weapon as powerful as the Helios would cripple or completely rip apart a ship as large as the Sath if it were made of conventional materials. So what does that tell us? Materials science has advanced several centuries by the time of FS, and they have hulls that are known to withstand Helios bombs on a corvette. The Shivans have a
cruiser that can withstand a Helios explosion.
There is one fact that you seem to be avoiding at all costs here: the Shivans are more technologically advanced than we are, and they have vastly superior numbers. Their numbers alone could overwhelm us. How exactly would you defend against 100 Sathanas juggernauts?
I want you to answer one thing, or I'll consider your entire argument to be a bunch of unverified BS that isn't supported by any canon facts about the GTVA and weapons in the FS universe. And I don't want any "Tesla could do it" crap either, I want an actual feasible strategy based on existing FS canon about weaponry and limitations in GTVA production ability.
How would you attack a fleet of 100 Sathanas juggernauts, their supporting ships, and an SJ Dante, with the resources the GTVA has?