Rikki, this is very basic left hand study, , but it leads to the bigger story.

When you see a --- a C6, Cmaj7, C6/9 Cmaj9, play a C chord.
When you see a --- a Cm6, Cm7, Cm9, Cmmaj7, play a Cm chord.
When you see a --- a C9, C7b9, C7#9, C11, C7b5, C7#5 – and there is more –-- play a C7 chord. In math they call this, reducing it to the lowest denomination. Equals; making it simple to understand.

Key of C Major:
C G7 C --- C-E-G D-F-G-B C-E-G I-V7-C
C F C ---- C-E-G- C-F-A C-E-G

Substitute Dm7 G7 for G7
D-F-A-C (Dm7) D-F-G-B (G7)
Do this until it comes easy. Then do the same for the key of G major, and F major. I am not concerned with the bass line here, just ease of fingering. All the chords are very close to each other.
There are more reasons, but not now. If you can do this easily, we will go to the next step.
John C.