Well, the thing is, there's a LOT of highly specialized technical knowledge out there. Like, more than would fit in dozens and dozens of people. But the pillars of modern technology are:
Fabricators and fabricator rights management, which can produce arbitrary objects like structure mages if fed the right materials and given time and energy. A fabricator can build a mining robot and then an ore processor and then another fabricator and then the two fabricators can build TWO mining robots... Repeat forever. Except the patterns for this are all patented and restricted heavily so that the corporations that researched and developed the products and designs can earn their due profit from the sale of said designs. Of course, there are lots of failsafes and obfuscation techniques built in to make it hard to 'crack' a fabber and produce your own stuff, or make unpaid copies of some corporation's products. Copyright law is, of course, extremely on the corporations' sides here, to the point where they can charge whatever they wish for basic necessities and people have to fall in line.
Computers, software, and virtual intelligences, especially the VIs. VIs are computer programs that can 'learn' what to do, and are narrow and restricted enough in the right ways - like not actually having emotions, or having certain kinds of long-term memory, or being able to learn anything outside of what they're specifically designed for - to not actually be people. There are quite a variety, and most people work with a VI in their daily work, guiding or curating or double-checking its work. As a special effects engineer, he would craft specifications for a VI to paint explosions, spaceships, background characters, or other things to insert into shows. Creating full computer-program-people, artificial general intelligences, as slaves was popular for a little while but is currently illegal - and (he sighs wistfully) most of the knowledge of how to do it was deliberately destroyed.
Warp Drive and Korolev-Chandrasekar Gates! These are what granted humanity the stars! Warp drives propel ships across interplanetary distances without the need for excessive amounts of fuel. The KC-gates use portals to connect two points of space around distant stars, dodging the need for long durations of interstellar travel at sub-light speed. How exactly the physics here work is extremely weird and complicated and secret, with the Solarian Navy coming down hard on anyone who fucks with warp drives or particularly the Gates outside of extremely narrow approved bounds. Even the known blueprints for drives are utterly black-boxed: They're so complicated that it's impossible to tell how they actually work, what's necessary for the function and what's just there to make it hard to tamper with.
Biological augmentations and cybernetics are very far from Alex's expertise, but Cernonnus Botanicals has thousands of gene-lines of engineered animals, augments, plants, specialized viruses of all kinds. There's special modifications for spacers living in zero-g, for a cure to aging in humans, advanced medical treatment for any kind of disease or trauma, dozens of different kinds of modifications - like poor Helen the foxgirl - plants adapted to suck up toxic materials or bacteria meant to make an entire planet habitable, custom pets, so much potential and all of it crushingly expensive.