Just my opinion if your happy with the a51 the a16 should be simular in performance there is the a56 being released might want to see if you would like
Agree with @meself and A51 should have been released in 2020, so it's closer to the end of its life anyway. A56 is the current successor in that lineup, but A16 was just released October last year and will provide about the same functionality as the A51 without eating too much into your wallet.
