No, when using wording like "outrageously powerful", that's exactly the comparison you elicit.
I'd be fine with "best in class" or even "unbeatable performance per Watt", but I can absolutely guarantee you that an iPad does not outperform any current popular-with-the-ML-crowd GPUs...
I think a comparison to the 4090 is unfair, as there is no laptop/tablet with an rtx 4090 and the power consumption of a 4090 is at ~450W on average