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.
The flip is possibly doable, but as someone with a Fold4 there simply isn’t room in the device to start incorporating screws in the half with a screen on both sides. Only way I can see it working is putting the whole battery on the side with a normal back, but there isn’t enough room for the same size of battery. It’d probably also throw off the balance in the hand when open.