You have to keep in mind that power tool batteries are kind of the worst case scenario when it comes to lithium battery safety because they get knocked around, shoved into tool boxes, crushed, etc. of all the consumer products most at risk of fire, tool batteries are up there. That’s part of the reason they are so expensive. At the same time, knock off 18650 cells are generally well known fire hazards on their own.

I think it’s up to you what your risk tolerances are, but if a DeWalt battery burns my house down, at least you have a company to sue. If the Temu battery does the same thing, you are going to be SoL. I’ve been building and repairing various kinds of packs for more than a decade and am quite wary of random bootleg cells. I’ve never had a real Panasonic or Samsung cell fail, only knockoffs.