Underpowered in terms of RAMs, storage, and possibly GPU. Agree that M2/M3 are faster and have better battery life. Weight/heat to me fall under build quality, not specs.
Next you're going to tell me the new I6 turbo engines are "underpowered" compared to the V8s they're replacing, even though they have more power, more torque and in the same vehicle produce faster 0-60 and 1/4 mile times.
Your definition of "underpowered" is interesting to say the least.