Are they going to have an exception for waterproof phones? Seems like it would be challenging to implement replaceable batteries while maintaining waterproofing. Are there any waterproof phones on the market with removable batteries?

Why? You can use an o-ring around the seal and screws to press it together. Even simpler: a water bottle like you might bring to the gym or while hiking is water proof, without needing glue. It is a solved problem. But the solution adds tens of eurocents to the cost of the phone, so the manufacturers won't do it unless they are forced to.

Sony made a water-proof phone long before fixed batteries became fashionable.

I Can change the battery on my waterproof watch just fine

Before they found out they could sell more phones glueing batteries, my waterproof phone had a replaceable battery and a 3.5mm jack.