Doesn't mean they use the same chemistry. There's a lot of different lithium batteries.
Samsung isn't even using the latest\greatest tech in cell phone batteries. The Redmagic 10 pro uses a silicon-carbon anode based battery in a dual cell form. It means fast charging is split between 2 batteries so there's less battery damage on a recharge, and the chemistry is more energy dense.
Also, it seems the cell phone companies self assess the tests and report them to the EU, so take the whole thing with a grain of salt.
It kind of isn't. The EU is giving the cell companies guidelines on how they should test their batteries, and then report their numbers back to the EU. So "Apple" are testing their apple phones and then telling the EU their alleged numbers.