What is the current status of making specialization stable?

Is there a sound method of specialization that's in development?

Both specialization and min_specialization are unsound.

The only idea for sound specialization I can find (always applicable impls) has an open issue that hasn't been touched in 4 years https://github.com/rust-lang/rust/issues/48538

Is there no consensus on what sound specialization should look like, or is there a RFC that's being worked on?