Yes. If someone says that the scale to "use" on G7 chord is a G mixolydian, that to me is wrong. A G mixolydian is a mode to be used when you have a composition in that mode.
Furthermore the notes G A B C D E F G may well fit when in the key of C (Dm7 G7 C) but not at all good if you are in C minor.
So I look at that whole chuck of chord sequence as a key centre:
Dm7 G7 C implies first of all the notes of a C scale over all three chords. not a separate scale fo each chord (D dorian, g mixolydian, C major)
Similarly Dm7b5, G7 C minor forst of all implies a scale of C minor over all three. (That becomes slightly more complex as you have a choice of different minor scales. My "go to" would probably be harmonic in many cases)
BUT we should always ideally think of scales as a collection of notes to choose from to make up melodies (so can be a scakle but could just bea phrase) , while knowing the actual chord tones and their tendences (e.g. in G7, the note B has a conventional tendency to want to resolve to a C)
In practice then:
If I have G7 to C I will take the G7, ie G B D F, and know those chord notes then fill in with the scale of C:
G A B C D E F G
If I have G7 to Cmin I will take the G7, ie G B D F, and know those chord notes then fill in with the scale of C minor:
G Ab B C D Eb F G