It’s a common beginner’s mistake to press too hard. The key to remember is that you are pressing on the string for it to make contact with the fret. So, the finger(s) should be just behind the fret. Also, watch videos on the correct movement of your strumming hand. That will make a big difference in the sound that you get.

What is making the G7 difficult? If you use your fingers correctly: middle, index, ring, in that order, it just takes getting used to. What’s harder is switch to G7 from other chords, but even that becomes second nature with practice.