As someone who is pretty obsessed with my iPhone battery life I love articles like these. I think you might have missed one big other factor though, also based only on rumour at this point obviously.
Isn't it a pretty widely accepted rumour that this year's iPhones, or if not all then at least the Pro models, will go up a generation in terms of the Qualcomm modem being used, from the X65 to the X70? Qualcomm are making some really big claims for the X70 in terms of power efficiency increases at least for 5G, not sure if 4G will also benefit. If Qualcomm delivers improvements across the board, not only power efficiency of 5G data transfer but also 4G data transfer and maybe most crucially energy used while simply maintaining connection to a base station, that could deliver a quite significant improvement to battery life.
For my use case Apple could deliver an absolute massive boost to battery life for my preferred Pro Max model by giving other apps access to the full refresh range of the display. To support the introduction of always-on-display the Pro screens can clock right down to a 1Hz refresh rate. Almost all of my iPhone screen-on time is really static with well about 50% of it in Kindle reading ebooks and other stuff like looking at WhatsApp, reading news etc is also quite static. I would think that I could probably get at least another full day of battery life if Kindle, WhatsApp etc had the option to drop the screen refresh rate right down when the user is essentially doing nothing except staring at a static screen with the (for a computer) very occasional scroll.
If Apple did the above, maybe doing it automatically in the background for apps based on GPU activity so that app developers didn't have to explicitly code for it (unless they wanted to override the behaviour), it would be interesting to see how that would impact your simulated real life battery life tests.
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