First year where (number of Starship launches that year) > (number of Falcon 9 launches that year).

Any launch that clears the pad counts as a launch. Suborbital launches count. Falcon Heavy doesn't count towards the Falcon 9 number.

If either rocket is renamed but is still obviously the same rocket, it still counts towards its previous name. If either rocket is redesigned but keeps the same name, it still counts.

If SpaceX is renamed, acquired, or splits up, any launches of these rockets by any such successor companies still count.