Is the Tamron 28-300mm f/3.5-6.3 Di VC PZD Lens sharp? This page visually answers that question. Shown above are 100% crops from a lab-captured 100mm f/6.3 test image. Observe the contrast and resolution of these results.
Is the Tamron 28-300mm f/3.5-6.3 Di VC PZD Lens set to 100mm f/6.3 sharper than the Canon RF 24-240mm F4-6.3 IS USM Lens set to 240mm f/8.0? The image quality comparison above also answers that question. Switch between the results to see the sharpness differences between these lenses.