The Exynos 9611 on the A51 and the Snapdragon 730 on the A71 are clearly meant for mid-range smartphones, but the imaging features on these models are already more advanced than anything Samsung has put on previous flagships. In this respect, the A51 features a 48 MP main shooter, while the A71 comes with a 64 MP sensor, and both get a 32 MP selfie cam.
https://www.notebookcheck.net/Samsung-launches-quad-cam-Galaxy-A51-and-A71-mid-range-phones.447176.0.html
A71 looks impressive and nice but it is too tall. Samsung should consider ergonomics and usability. With a single hand, you can't reach the top edge with your thumb to quickly swipe down on such tall phones.