To allow the manufacturers to adapt and phase out?

Totally agree! It's seemingly gotten worse recently too. My phone is 5 years old and I was still able to replace the battery at home but it took special tools and a hair dryer. The newest Pixels and Galaxy phones look impossible to do with my current skillset.

Things like Fairphone and the HMD Skyline should be the norm going forward.

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.

the phone heats with use as well. but yeah Samsung is known for its high build quality. it's not like they made devices that explode or anything.

It's already enforced. All devices sold in the EU from 2027 will need a user-replaceable battery.

We're going to see some manufacturers come out with those devices sooner, though. I hope.

Also, the batteries need to be available at a reasonable price to the user.
Or they'll start scheming