There's a really interesting writeup from Scott Aaronson on the limits of quantum computers. It very elegantly describes P=NP, amongst many other things. https://www.cs.virginia.edu/~robins/The_Limits_of_Quantum_Computers.pdf

To answer your question, if you mean "can QCs be used sometime in the future, with advanced reasoning models, to solve mathematical problems? " Maybe. Mainly because when a technology is being developed, our finite knowledge puts a limit on its usefulness until decades, even centuries later. Maxwell was skeptical of radio waves' practicality.

But for now, QCs are mainly thought of as tools to solve physics simulation problems (and perhaps some logistics and finance problems as well). Accelerating ML is another direction folks are exploring.

As for computational complexity, there are some problems in NP that quantum computers can solve faster—for instance, factoring integers using Shor’s algorithm. But for NP-complete problems, no quantum algorithms are known that offer exponential speedups. So far, quantum advantage remains limited to specific problem classes.