Not sure how this works in Philadelphia or with the GOP there and the article is not clear, but I would think that Daphne Goggins is not the only GOP endorsed candidate in Philly.
The GOP in Philadelphia essentially is toothless. There has not been a Republican Mayor since the early 1950’s. Philadelphia is a one-party town. The Republicans are given a few crumbs, such as patronage or control of the Parking Authority. They also are given a minority position on City Council. Overall, the Republicans do very little. Every four years they put up a sacrificial candidate for Mayor. But even with all the shortcomings, certainly the GOP could have come up with another candidate.