I've also had bad luck with power banks that can survive outside more than a little while. Not moisture, you can seal that out, but heat and cold seems to kill the batteries.
There are so many factors that it's a near-impossible task. And even if you somehow managed to do so, it would already be obsolete by the time you stopped typing.
The datasheet (for each of the ESPxx, regulator, etc) will specify power consumption in different states. But sadly there's a lot of misleading amateurish pseudoscience in Arduino-land so you're best to ignore everything else (which would even include a guide like this, for example).
The hobbyist solution would be to find some obscure product on AliExpress with a holder for 2xAAAs and a 5V boost regulator with a USB connector. It's janky and inefficient, but that'll power your board, or your iPhone.
The 'proper' solution would be to then take this prototype to an optimised design in your ECAD software of choice, integrating a AAA holder and choosing an appropriate regulator, and having some PCBs assembled.
I'm not sure what else you could want. If the latter sounds daunting to you, it would be very easy for even an inexperienced EE on Fiverr to whip up for you.
Given a power source and board with defined power requirements (e.g. say 3.3v upto 150mA) if we can easily find what commonly available components are needed and how to wire them up (with tradeoffs) is sufficient.
Here's an excellent video that touches lightly on what I meant. https://m.youtube.com/watch?v=heD1zw3bMhw .
PS: If you find the video format of tutorials useful for learning about electronics, Andreas Spiess and Great scott channels on youtube have very good content that is helpful for beginners.
If you're designing your own board, you would simply enter 3.3v and >150mA into the parametric search on Mouser, Digi-Key, TI, etc and pick whatever part takes your fancy.
This is so simple that there isn't any need for a guide. The datasheet for whatever regulator you choose will tell you the recommended input capacitance, output capacitance, inductance, any configuration resistors, etc.
Same goes for battery charger ICs, which can be just as simple or far more advanced, and there are new devices being announced all the time for everything from tiny energy harvesting applications to USB PD, which is what I mean when I say it'll be obsolete by the time it's announced.
It's daunting at first but you need to take the plunge: find a part that interests you on Mouser, integrate it into a design according to its datasheet, and order some PCBs. You'll be amazed how accessible it is.
Drives me crazy just how much people don't realize that they don't know and are just spouting unfounded assumptions.
Most guides out there work with dev boards that are powered by usb. It's great to see a section dedicated to power them with alternatives like LM-1117.
I'm still hoping to find a guide dedicated to power management of espxxx boards that includes guides for powering them with a range of sources like coin cells, aa, lithium, 9v, 12v batteries etc along with a primer on different features (like sleep modes) and their impact on power consumption to maintain the battery life.
I always see mentions of all these interesting diy projects but not how they are powered. So, its difficult to get a complete picture of the maintenance needed and their usefulness in the long term.