As someone who also possesses an unused advanced maths degree, I would suggest pursuing mathematics for the sheer fun of it first and then decide in a year if you really want to be involved in statistical modeling, ML, deep learning or whatever.

You may end up deciding that being an insurance actuary is the right challenge: there are multiple exams to pass involving a lot of maths and the pay is quite good.

For recreational maths I’d recommend rereading Polya and playing with “Crossing the River with Dogs” and “Math Recess”.