That's just false. AMDs newer U models have TDP and performance per watt at the same level as the M1.
Apple has other advantages with the M1 (like running iOS programs, more optimised for their software and so on), so they still benefit from having their own chips. M1 is great, but it's not magic.
Apple M1 - 10 watts TDP
If the numbers are accurate, then it is close. However, each company measures TDP in different ways. Plus AMD can boost to 30W for short periods of time. Obviously the boost is good when you need it. The big question, how does this affect battery consumption?
That said, AMD's biggest issue is supply. I don't know if it is supply issues from TSMC, or component issues with the OEMs. But it is nearly impossible to buy a 5800u.