My pick is the Mi K20 Pro/Redmi 9t, I know its a year old, but its specs are current gen so I feel its worthy. The 9t Pro at $800 is an even more amazing package with the sd855 platform. but for $1000 Id be going the Mi10 Pro with its SD865 and higher quality 108Mp camera setup.
For $480~ you get a lot of bang for buck with the amoled and qualcomm 730 chipset, not to mention 6GB ram and a handy camera (not quite the 108Mp beast on the Mi 10x range, but good enough).
i feel the a51 is good but it just lacks the power of the Xiaomi.
What is your favorite mid ranger?