alt Hacker Newsx86 is way more complex when compared to ARM processors, as a result their TDP is way higher when you request performance from them.
Intel had to reduce the frequency of their processors when running AVX2 instructions and the AVX2 frequency of the processors were non-disclosable to anyone.
Also, benchmarking Intel processors and publishing these numbers were forbidden in some cases. I don't know whether this ban is still in effect.
x86 processors can't keep up with the ARM processors TDP and thermal profile wise. So they slow down a ton when running on battery. See Jeff Geerling's last video on Apple Neo vs. some Intel laptop. It's as "efficient", but slow as a newborn tortoise learning to walk when unplugged and trying to get the most endurance out of the battery.
My M1 Mac gets almost 2 days of low-intensity use after ~6 years of use, and it got warm once or twice because something ran away in the background for tens of minutes.
Being mistaken on the CISC vs RISC debate (besides, modern x86 is closer to RISC via micro-ops then old school CISC) is understandable. There is a lot of misinformation out there and myths, plus, it just feels right to consider CISC overly burdened, etc. TLDR: Intel x86_64 is closer to RISC then you likely think and Apple Silicon arm is closer to CISC then you likely think. These lines are blurry and have been for decades, very much for good reason.
But talking this authoritatively on something without doing the reading, that's grating: https://chipsandcheese.com/p/arm-or-x86-isa-doesnt-matter