Thatcher cut income tax early in her time. But she doubled VAT from 8% to 15%, raised National Insurance, and local taxes, all regressive taxes which hit the worse off harder. So it can’t be claimed that her tax cuts increased government income - unless you can find evidence to back this up (I can’t). The results of her policies was inflation reducing, but very high unemployment and low industry investment for years. In fact by about 1984 she had abandoned the policies of monetarism but kept the rhetoric. We were back in another recession when her mates kicked her out.
What she didn’t do was borrow huge amounts, she believed in balancing the books. She was helped in this by the benefits of North Sea oil and high oil prices keeping the £ strong. She also added to her coffers by selling off the state’s wealth - a one time only binge of privatisation. We don’t seem to be following the same script now.