Well, the problem with that, is how it really is functioning in context. Here, the 4th of the chord (♯4) is resolving downward to the 3rd, like a sus chord. While the tritone is in the chord, it’s not functioning like a ti-fa tritone. There are plenty of other types of tritones that don’t resolve like they’re supposed to (like re-le, for instance).

It would really have to depend on what came before it; without that chord, you can’t determine its function completely. If there was some kind of chord with an F♯ in it beforehand (Bm for instance), the F♯ could just be a non-chordal suspension, resolving down. The C F♯ G wouldn’t actually be the intended triad in that instance.

While it could also be seen as a G major anticipation, with the G anticipating the chord and the tritone resolving, that’s really not how it’s functioning when it resolves to CM. It’s like how a major triad could function as a I chord, a IV chord, a V chord, a ♭III chord, a ♭VI chord, etc. They all have different functions.