Kind of related but one thing I like I do on occasion is check out various enthusiasts subreddits for niche things and see what the community go to is. Like AA batteries and how Eneloop batteries are the gold standard.
Browsing the mechanical keyboard sub, the buy it for life sub, and any other subs like that was amazing and such a deep rabbit hole for the first time!
Batteries are rated for a certain continuous current draw, and if you try drawing too much, you're going to have a bad time. Some of these flashlights can draw a ridiculous amount of power, and if you're putting a cheap knockoff 18650 in it with no internal protections, it's not going to be a fun time.
It's the same issue people had with vapes exploding. The original included batteries might only be rated for a continuous draw of say, 10A, and they're adding these crazy high wattage coils trying to get 30A from them.
Wurkos fc11 I think on Amazon. Fantastic. For these crazy lights you mainly just need nice high draw 18650s from a reputable store online and a nice 18650 charger. I had a cheapo charger from Amazon that screwed 2 batteries and they wouldn't cool down, hot to the touch for hours. A bit concerning lol
Overkill? Maybe. Quite nice to have a dark country road lit up well enough to light up the road close AND far (most headlights have a tight beam that only does either).
Also I like the reusability/repairability of productd based on 18650 cells
I found this larger 14,000 lumen one from Emisar for $88, but no batteries are included, so you'd also need to buy 3 high drain 18650 batteries (~$20 total) and a charging cradle for them ($18 from Emisar) separately.