This isn’t how people work in the real world.
I do not have a single client that would think earning another £10,000 to keep only £2,600 of it would be worth their time.
I am not defending the student loan system.
I am saying you're still always better off earning more.
In my case, of every extra £ I earn I pay 40p tax, 2p Nation Insurance, 13p pension, 2p levy to Labour, 9p student loan, 8p tithe - but that still leaves me 26p better off!