It had been in the works for a while, but now it has formally been adopted. From the article:
The regulation provides that by 2027 portable batteries incorporated into appliances should be removable and replaceable by the end-user, leaving sufficient time for operators to adapt the design of their products to this requirement.
I am pretty sure there were water resistant S class Samsungs with snapon back covers. Around 5th/6th generation.
There were, I had every odd Samsung flagship phone since the S3, and two of them (S5 and S7 or S7 and S9) were waterproof with removable backs to change the battery (and SD card)