In my view, we need to move the goalposts.

Fraud detection models will never be fair. Their job is to find fraud. They will never be perfect, and the mistaken cases will cause a perfectly honest citizen to be disadvantaged in some way.

It does not matter if that group is predominantly 'people with skin colour X' or 'people born on a Tuesday'.

What matters is that the disadvantage those people face is so small as to be irrelevant.

I propose a good starting point would be for each person investigated to be paid money to compensate them for the effort involved - whether or not they committed fraud.