For me, lights with higher lumens are generally reserved for duty carry in which you'd need to be able to flood a room with light, as you progress through the structure that you're clearing for any threats. I don't carry anything above 1350 lumen output, and that lights' output is able to remain stable for approx. 10 minutes straight from turn on, before starting to step down. Even when it steps down, it's barely noticeable at about 700 lumens, where it stays for quite some time. With that said, generally on duty, you're light won't be on steady for a prolonged period of time.
Looking back throughout the years, the longest time I've needed to keep my light on was clearing a huge structure with hundreds of rooms and multiple floors. In all, the light was on for roughly 45-60 minutes. Lucky for me the light I was using had a fresh battery and still had about 20-30 more minutes of runtime left when I was done. Even so, not really a big deal as you normally would either carry a smaller back up flashlight or an additional battery in your bag at least.
That situations was really the exception generally speaking your done with your light well within 10 minutes on average. So with something like an 18650 / 21700 you can certainly power a light that's around 1000 lumens for that sub-10 minute period of time that you need all the light you can get.... and if it goes longer, it steps down gradually... but not enough to hinder whatever it is that you needed it for in the first place.
Basically, if you (god forbid) have the potential to find yourself in a gun fight, I strongly recommend you carry a stronger light. (not a gimmicky one, or one with 2, 3, or 4k lumens... Something that's reliable and you can depend on, generally with 1 mode than turns on max output).
Besides that, really you don't need anything super powerful. For general EDC tasks, 99.9% of the time, 50-250 lumens or so will do the job. Over the past decade my go-to EDC light has been the 4sevens Mini ML. Absolutely LOVE this light. It was tiny, but yet powerful and simple and easy to use, low/med/high and very reliable. Max output was around 200 lumens which I rarely ever used, generally it would be on low or medium.
Big reason I found such a liking to the light is that its so small and lightweight, it's acceptable to carry it in addition to my tactical light... and it really doesn't add any bulk or weight to you for the day... but I had a capable and useful EDC light for general tasks.