When you look at the regulation [1], you see several potential loopholes.
Firstly, the regulation does not say an appliance MUST allow removal and replacement of batteries by end-users, but SHOULD allow it.
The capability is not meant to allow for swapping batteries to increase user comfort (e.g. by replacing a dying one with a new one), but primarily to allow for disposal and recycling of the battery. This is likely to create new EU legislations that put more burdens on the end-user (e.g. having to remove and separately dispose of the battery instead of dropping the device off at a recycling center).
Then, in paragraph 38, a battery is considered replaceable by the end-user if the end-user can replace it with generally and commercially available tools. A manufacturer could, for instance, make replacement dependant on a tool that they individually sell for an absurd amount of money, and would be in compliance with the regulation.
In paragraph 39, the text shows again that there is no general requirement for a manufacturer to allow user-replacement in all cases. Some example given when this is not considered necessary are water-resistance, and safety concerns. A smartphone manufacturer could easily argue that the battery is too fragile to be handled by end-users and doing so risks lithium fires.
These exceptions then are codified in Article 11, which uses 'shall', not 'must', and which gives us another reason when this does not apply - for devices which need to have power constantly, e.g. for the integrity of data collection. Which you could easily argue that smartphones fall under.
In subpoint 4, it points out that the list of excepted devices can be extended whenever they so feel like - all it takes is a series of kids who start burning themselves while mishandling batteries, ideally on social media, and smartphones are explicitly exempt after the outcry.
[1] https://data.consilium.europa.eu/doc/document/PE-2-2023-INIT...