Is the Sony FE 20-70mm F4 G Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 24mm f/4.5 test image. Observe the contrast and resolution of these results.
Is the Sony FE 20-70mm F4 G Lens set to 24mm f/4.5 sharper than the Sony FE 24-70mm F2.8 GM II Lens set to 28mm f/8.0? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.