Zen is also an SoC, but with off-chip memory, this brings other advantages.
Most importantly, Zen 4 is a chiplet design, so for the same amount of cores it will be cheaper to make than the M1 chip.
As for performance per watt, Renoir in low power configurations matches the A12. I would really doubt that a laptop Zen 4 on 5nm LPP wouldn't pass the M1/M2 in both performance and performance per watt, because Renoir is on 7nm with an older uArch and gets close.
Most importantly, Zen 4 is a chiplet design, so for the same amount of cores it will be cheaper to make than the M1 chip.
As for performance per watt, Renoir in low power configurations matches the A12. I would really doubt that a laptop Zen 4 on 5nm LPP wouldn't pass the M1/M2 in both performance and performance per watt, because Renoir is on 7nm with an older uArch and gets close.