There isn't likely to be a 245. Garmin's range was already too crowded, and as they kept adding features to to Vivoactive line, it basically squeezed out the 245 from below. It's a shame because the Vivoactive 3's lack of physical buttons make it a poor substitute for the 235, but I think Garmin would say that if you need physical buttons, that's where the 645 comes in.
Though, to be honest, there's nothing wrong with the simple 35. It has the core functionality you need, physical buttons, and a low price.