These are at least credible suppliers. If you replace w an eBay battery the results can be laugh out loud terrible. Years ago I thought of saving money this way - but didn’t - I actually don’t fully understand why apples batteries are so much more reliable than these third party ones - what type of bms is in them?

Ironically HN was railing about the non genuine notification appple provides buyers of used devices - very much worth checking when buying though.