Not all; it looks like the M1 running full-tilt is slightly less efficient for the same perf than the M1 Pro/Max. (I.e., the curves intersect.)

Yes, but only at the very extreme. It's normal that a high core count part at low clocks has higher efficiency (perf/power) at a given performance level than a low core count part at high clocks, since power grows super-linearly with clock speed (decreasing efficiency). But notably they've tuned the clock/power regime of the M1 Pro/Max CPUs that the crossover region here is very small.