Not gonna lie, I don't think SIDE is particularly important to TRUST's performance. What matters is recruitment and basing infrastructure. We can churn out weapons for them later.
Because real talk, either we have several years to equip TRUST with whatever we want for a big war against whoever's willing to defend Mengsk, in which case there's no urgency...
...Or we're trying to speed-run this, in which case we're screwed anyway, because what'll matter is us laying the groundwork with Personal actions, far more than whether TRUST has shiny kit. Because the only way to pull off a speed-run that doesn't lead to a bad ending is to assassinate Mengsk as quickly as possible and replace him with someone else to sit in the Big Chair before the warm spot on the throne cools off. And that's going to rely far more heavily on whether we've made good allies than on whether we have the latest rockin' body armor for our paramilitary troopers.
We've run out of options that directly help the common people in Research. The Super-Heavy Cargo Freighter helps the economy, which might ideally also help people in general by improving transportation and goods availability, but even that is to be honest conditional on access to things being hauled being equitably (or, let us not hope for a miracle like evenly, and even say 'with any degree of fairness') divided out.
I'm not going to dispute the rest of what you said, but this paragraph misses something important:
The status quo is
worse when it comes to commercial interstellar spacelift.
If there is only a little spacelift capacity and it is of limited efficiency, then with someone like Mengsk in charge,
ALL that capacity will be reserved for the most 'critical' (read: important to the military-industrial-security complex) projects. Note the part where a labor battalion at Augustgrad, even when given a coupon for a vacation on another planet, has a three-year wait list to actually get transportation to that planet. I'm betting there's no shortage of cargo transportation to move giant gold-plated statues of Arcturus' daddy issues around the Dominion.
Even 'critical' spacelift demands are being shorted as-is. If we want
any spacelift to go to things normal people actually want or need, we need massive expansions of capacity. The effect will not be indirect. It's like the effect of shipping food into a place under famine conditions; the effect of an increase in availability is disproportionate precisely because there is so very, very much deficiency.