OK music theory twitter, a morning question. If you want to come into it cold, riddle me this:

What would you call the chord in m. 4 of this excerpt, with the Db in the bass?

Context to follow in thread.

This is a fascinating ("remarkable!") passage from 2/3 of the way through Amy Beach's "Autumn Song" (1904). The song begins in F minor, and at this point has made its way along a series of R/P transformations: F-, Ab+, Ab-, Cb+. That's where we're starting in this excerpt.

As I hear it, that Cb in m. 23 is enharmonically reinterpreted as B in m. 24, the third of a G7 chord: V7 of V as we make our way back into F a measure or two onto the next line. That C7 is delayed with a suspension (m. 25) and then this Db in 26.

I'm inclined to read it as a chromatic alteration of a G7 chord: the 5th of the G dominant 7th we've just heard is flattened, so that it's a particularly intense upper neighbor to C. But I'm worryied that I'm somehow missing something, hence the question.