With this many miles, I would check the throttle body itself.
A couple of things can happen, first, you can get oil/carbon build up that causes rough idling and poor part throttle performance. So, I would check, and likely clean, the TB. Soft nylon toothbrush and plenty of solvent with the body off the car. Get a new gasket to put it back on the manifold.
Next, the actual sensor (throttle position sensor, essentially) and the actuator (which moves the throttle) can simply wear out with time. Depends how it’s built, but a worn out TB is a possibility. To check that, you need Mazda-specific diagnostic tools that can “sweep” the body, that is, run it from full closed to full open, and check the readings.
Don’t go throwing parts at this. Clean the body first. Perhaps you’ll get lucky and that’ll the the problem.
Then, if that doesn’t work, you need to check fuel pressure, do a throttle body sweep, etc... proposer diagnosis with proper tools. Too many possibilities to just fire up the parts cannon and hope you hit the target.