I'm in the UK (hence the reference to National Insurance). The (roughly) equivalent legislation here is IR35 [1]. But it's not too onerous and there are plenty

I'm in the UK (hence the reference to National Insurance). The (roughly) equivalent legislation here is IR35 [1]. But it's not too onerous and there are plenty of people who successfully pay fairly minimal tax while complying with IR35. [1] https://www.gov.uk/guidance/ir35-find-out-if-it-applies https://www.gov.uk/guidance/ir35-find-out-if-it-applies