Unless you have a specific need for a light to be really small and lightweight, I'd start with 21700 lights (or even higher if you like the idea.) I actually think the ergonomics are even better with 26650/26800, as those lights are often around the same thickness as the old D-cell maglites...
I honestly doubt we will get there before destroying ourselves. We have shown no ability to develop a balance with our ecosystem. Our M.O. is to take and pollute and overbreed until everything is ruined, and I see no signs of that changing.
I got mine for $40 apiece here, and it took less than a week from order to arrival. Power bricks for both. It can be hard to tell exactly which version of something you're getting on AE, and I doubt the returns system is very fast.
Vapcell S4 Plus is my favorite. I bought a couple of them. Charges at up to 3A per bay, displays plenty of info for whichever bay you're viewing, auto/manual control, and there's a notification beep when the batteries are done charging (I like this, some people don't.) There are also capacity...
I'm honestly not sure if they still make protected 18650s. The reason for a battery to have protection built in is just in case a flashlight doesn't have LVP, but they pretty much all do now.
Anyhow, for most 18650 lights, the Sanyo NCR18650GA 3500mAh 10A is the best overall IMO.
If you have a...
My first "real" flashlight was a 4 D-cell maglite in the mid-late 1980s. I don't know where it ended up, but it sure was nice to have at the time. Before that, I had some junky Radio Shack yellow and black plastic flashlight with a magnet on the side.
Convoy makes some great lights, but the S11 sucks pond water. Ugly dark beam artifacts including a black ring in the corona, and the tail switch is too recessed. If your thumb isn't lined up perfectly with one of the open sides, it hurts to press down on it (because your thumb hits the metal...