Crypto mining isn’t that hard to understand; it has nothing to do with solving “complex mathematical problems.”
Instead, just imagine it as the world’s biggest and most environmentally destructive random number generator. Get a correct number and you get to create a block (and get a reward). It’s a rather “dumb” process that only produces useless output. In Bitcoin produces 260 quintillion of these random numbers every second of the day, drawing more electrical power than Sweden to do so.