Is the Canon EF 40mm f/2.8 STM Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 40mm f/2.8 test image. Observe the contrast and resolution of these results.
Is the Canon EF 40mm f/2.8 STM Lens set to 40mm f/2.8 sharper than the Tamron 24-70mm f/2.8 Di VC USD Lens set to 24mm f/2.8? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.