Completely with you on the marking of exam papers, what an utterly soul destroying job. I felt nothing but sympathy for my lecturers who faced, as well, the challenge that the majority of their students spoke English as a second language. Trying to unravel meaning about complex themes from imperfect English must have increased the burden considerably.
We have challenges in academia in the UK, too. Many jobs are being cut and many more are very insecure. There are numerous challenges but one of them is that English universities have relied on income from foreign students (something like 98% of students on my master's course were not from England): it's highly competitive as a global market and the UK government keeps shooting itself in the foot by introducing immigration policies that undermine potential income.
Regarding working for The Man: yes, a life-long struggle but not insurmountable. You're trashed now, of course you are, and still with the pressures of securing money to live. Be kind to yourself (you have done and are doing your best), remind yourself that this is for now, and this is how you are feeling now, jettison anything you can where your time and attention is not immediately necessary (you can come back to it later), and focus on what must be done now.
Writing here I think is good - good for the soul to get it outside your head - and potentially to find support and ways forward. You mention the support of your family, which is critical, and you clearly have networks, because you mention other potential opportunities. Building your networks, strengthening the connections you have and making new, so called weaker, connections are also critical to finding your way out of this, both surviving economically and moving into a space where you feel you have more agency (I won't get into talking about revolution) 😂.
Some years ago, I co-ordinated a study about the value of networks for generating wealth (which can come in many forms, including income). Our own local study over two years demonstrated that the most frequent participants in a network secured between 2 and 4 times as much work as more casual participants. There are a lot of other studies that demonstrate similar results in many varied situations.
You might enjoy reading The strength of weak ties which talks about the work of Mark Granovetter, and Structural Holes by Ron Burt, I used ideas from both extensively in my work with some success, especially in my current role.
I hope this helps, and remember to take a walk in nature and generally to look after yourself 🤗.