Can you quantify your claim?

PTL’s highest SKU is comparable to the base M5 for only multicore perf at double the power use in every benchmark I’ve seen. It lags significantly behind in single core.

But I’d love to see a benchmark showing otherwise.

Just the latest I’ve seen https://youtu.be/7OxE7FwJPJM?si=b5T0PbmhUD1TXhX4

But I can find none that have PTL actually anywhere near M5 without strapping a much larger battery to the device

It's ridiculous to claim high and mighty that a chip that's not out yet is competitive. The only real way to test a laptop chip is in a laptop with the thermal choices made by the laptop maker. Hell, the M5 has been mostly benchmarked on the Macbook Pro, and that has a fan! The M5 is not going to be as impressive in the Air.

It's been five years since M1 and Intel has never been competitive in single-core perf per watt with Apple. It would be surprising if it changed.