” Another possibility is that Apple may open its FindMy network, used for locating AirTags and Apple hardware, to third-party hardware.”
It already is. Chipolo and VanMoof are two companies that piggyback on Find My to allow their devices to be located.
On an unrelated note; I think this is a bad move by the EU. Consumers should be able to choose an expensive, secure ultra locked down environment if that’s what they want, and if not… there are alternatives available.