There's always an implementation period with these things, also with the USB thing, to allow companies to build and sell phones that are already in the pipeline. Expect, just as with the USB thing, replaceable batteries to become a common sight quite soon and ubiquitous by 2027. You can already get quite decent smartphones with replaceable batteries but it's the usual suspects Fairphone, Gigaset, and (at least one model of) Samsung, those would also exist without the regulation. The "oh shit they actually passed it we'll need to re-engineer things" models from everyone else still aren't on the market.

And before anyone brings it up: Yes, you can make them waterproof.