The smallpox vaccine mandates were state, not federal.
The recent ETS struck down was a federal executive agency action. There are a few problems with the ETS. First, this is an area of law typically reserved by the states. Second, even if a federal law in this area is constitutional, none has been enacted. This was a pure end-a-round by the executive branch.
There is no inconsistency between the small pox decision and the OSHA ETS decision.
This current Supreme Court has let stand several state Covid mandates.