That's like your nan being frustrated that there isn't a single definitive guide to buying a laptop.
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).
I think there's some misunderstanding on the expectations. Documenting a combination of all the available peripherals, boards and power sources is virtually impossible but that is not what I meant.
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.
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 this new to electronics though, you're better off buying a hobbyist development board like any of those suggested in the guide. You don't need to concern yourself with this. Just plug in the USB cable.
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.
How to read that info from the sheet? Problem: I have my NodeMCU gizmo with sensors and stuff, that works while powered via USB charger. I want to make it portable and powered by AAA batteries. How do I do it? I feel that my nan would've had an easier time figuring out on her own what laptop to buy.
That's not what it's designed for. That's like asking how to run your iPhone on AAAs.
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.
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).