42k is not very low for an effecitvely entry level software engineer position. My first job in london after (a v. good) college was ~30k (5 years ago though, so sure inflation probably makes that ~32-33k now); finance was paying ~38-40k to grads back then.
Of course independent contracting is a thing; but you can't really be an independent contractor right after college (unless you built a great network, but then you're a ridiculous outlier), and even with job experience it's not a clear tradeoff.
But generally, it feels like you've moved the goalpost quite a bit here. Originally you claim the company exploits young graduates to build a sweatshop. Now we're talking about how they compare to the best tech companies around, and independent contracting.
Palantir London is decent in compensation from what I have heard (that doesn't speak for their other offices). They are however known for pushing 60h+ hours weeks very very bad until your whole life is your work, screwing people with shares that will never be paid, and sending people here and there around various locations.
Of course, there is also variance within a single company. It's possible that you've got a good position at Palantir.
That's 25% over a "standard" work week in the US. If that 42k is based on 40h/week, you'd need to earn 53k+ to "break even" on a 50+h/week (which Palantir appears to do).
FWIW, there are plenty of 40h-45h/week software jobs in the US that pay well into six figures.
The 42k figure is very low. That's likely for all IT roles including tech support and help desk.
If you are good enough to enter Palantir (they have some standards despite the bad PR), you are good enough to enter a real tech company.
Note that if you are a consultant going left and right to a new client regularly, you should make a comparison against being an independent contractor too.