I have bought many third party rechargable batteries from those sites over the years. Yes, slightly lower charge capacity compared to original, but no fires. And, yes, I know my sample size is small!

Don't know your exact timing but I run basically on Dells Latitude laptops for past 2 decades. Since its just for travel and not my primary workhorse, I buy used corporate ones for pittance (cca 300$ for models worth 1500 few years before), and swap battery myself for another original OEM one, they cost less than 100$ from original manufacturer. Its just 2-3 philips screws and 1 cable, anybody can do it. They last just as much as advertised on new ones and don't degrade much even after few years.

Batteries (and ie chargers) are one of the things that's utterly idiotic to shop around on chinese portals. You literally always get what you pay for (or worse) and can't punch above this threshold.