I agree with your overall assessment but > The Standard Model is the same kind of thing. Its maths is atrocious: a horrific blend of Einstein summation convent

I agree with your overall assessment but > The Standard Model is the same kind of thing. Its maths is atrocious: a horrific blend of Einstein summation convention, matrices chosen out of thin air, and complex numbers sprinkled on top just for fun. This isn't even coming close to describing the mathematical atrocities of the Standard Model / quantum field theories. Those are the easy and mathematically well-defined parts.