This is physics after all and 15W are 15W no matter if they go into an Apple M1 or an AMD Ryzen.
This is also where design decisions matter: for example, a while back I measured hashing performance for some boxes which needed to check data integrity and an Intel chip handily lost despite being faster on everything else because the embedded processor I was comparing it to had dedicate SHA hardware which was both faster and more power efficient than a generic x86 implementation. That’s ancient history now but I would expect Apple to aggressively explore opportunities to improve their stack like that since they control it at every level - for example, I believe benchmarks have shown Objective-C message passing is considerably faster on M1.
Apple has the advantage of developing and deploying hardware, OS and system software completely in-house.
AMD only supplies chips and basic firmware, both of which can be configured by OEMs/ODMs and the OS and software come from entirely different parties again.
So the usage profile depends on external factors, not just the CPU itself. In the end, however, a 15W power budget is a 15W power budget and an M1 under full load and a Ryzen under full load will have the same thermal output if configured the same (as far as power consumption goes).
How well the waste heat is managed is not in the hands of the CPU.
Finally, again, 15W TDP is not the same as 15W under normal usage. That misunderstanding appears to be driving most of your disagreements in this thread.
No. The CPUs can be configured to consume no more than 15 Watts, even if few OEMs do so. Same goes for the M1 - there's no difference with regards to this: both the MBP 13 and the Mac Mini have higher power limits and active cooling for that reason.
In fact, the latest U-series mobile Ryzen CPUs are even optimised to be most efficient at a 15W power level, contrary to Intel's Ice Lake chips, which get the most performance at a higher wattage configuration of 28 Watts.
That's a term in the industry with a specific meaning:
https://en.wikipedia.org/wiki/Thermal_design_power
The key thing to understand is that this is not measured power consumption while running the benchmarks and you cannot reliably compare the values even across the same product line, much less across chips — especially when we're talking about SoC designs where, for example, the TDP refers to the entire chip but the benchmarks being discussed are all CPU-focused and don't even exercise the GPU at all. We also know that TDP numbers are not a hard ceiling: there are some chips which under some conditions — most commonly but not always synthetic benchmarks — will exceed those figures, possibly by somewhat significant margins.
What you see there is are the power limits of the CPU (as reported by HWInfo64).
If you set the POWER LIMIT in the UEFI/BIOS, this regulates THE POWER consumption of the chip. NOTHING to do with TDP.
Why is that so hard to grasp for you? You can even measure the power rom the wall to confirm this. I am NOT talking about TDP here!
Those chips usually have 3.5-4GHz turbos, but in a fanless config, you'll never see them (and even with active cooling, you won't see them for more than a handful of seconds).