We both have 21s and 22s (him Ultra and me base)
It goes without saying, from us anyway ... the 21 and 22 far SURPASSES image and video quality of the S7.
You're doing something rwong, or you have a (doubt it) phone with defective camera or image processing software
I am sorry to hear of getting blurry pictures from the S21 camera, and can understand the frustration. If your photos and videos are blurry or poorly exposed follow our tips to get the best photos. If you are still having issues, we will make sure that your phone or tablet is in good working order. We'll also check for the most recent software and confirm no apps are interfering with the camera. Consult this guide for steps to take: https://www.samsung.com/us/support/troubleshooting/TSG01001424/
Please let me know if this helps.