Phones are moving to "chip scale" components: resistors, inductors, capacitors less than 0.25mm in size. And the chips themselves are getting smaller and smaller. The quantity of "hazardous" stuff outside of the battery is plummeting.
Making the battery removable and replaceable and having fully-reticulated battery collection networks would be nice.
On cost, though: there is the concept of "embodied energy". The AirPods cost $250 while the peanut butter jar costs less than $1, in part because a lot of energy is used to make the small components in the AirPods. (Not corresponding to the price difference, of course, but more energy.) Lots more steps in the production chain of AirPods, each with their own energy losses.
So buying new AirPods does have a bigger environmental impact than buying a peanut butter jar.
> you throw away more plastic after a family-sized Chinese takeout meal.
Flying from one side of the country to the other and back uses more carbon than several years' worth of Chinese takeout containers.