The paper describes the implementation including a detailed breakdown of the optimisation algorithm itself.
It's also plausible an iPhone 14 Pro could do it given its memory b/w, ops/s and that it can fit the SD model in RAM.
Hopefully someone will replicate it, and then we’ll know if they were telling the truth.
So you just assume these smart people are all lying ? And not just like hiding details but straight up saying it's on-device but faking it ? If so, I don't understand why that is your reaction.