In code, any developer whose differentiaton was clean code and knowledge of different technologies is now average.
In math, any mathematitian whose differentiation was to manipulate formal systems and know tricks of different domains will be average.
Fortunately, humans do more than syntax and search.
The bad news for developers is that if you know what the output of your program should be (which happens most of the time), almost all of the job is syntax and search to build the code that reproduces the output.
The good news for mathematitians is that for the majority of problems you never know the output, or you just know the output is either "True" or "False". There are some cases where you need something else, for example "a solution that blows up in finite time". For those cases AI will outperform you easily (see new Navier-Stokes solution)
So if as a mathematitian you were doing more than syntax and search, then keep doing that and use AI just for what its best.