There is very little difference between pro and air with apple m1 CPU. I see no reason to pay more for pro version unless you are planning to do a lot of heavy tasks like high res video editing or 3D sculpting. I'm waiting for release of m2 to get second hand or refurbished m1 at lower price.
I never buy brand new macs, it's a huge waste of money, you loose like 40% of it's cost the moment you unwrap it.
I believe it doesn't make sense to get 8Gb RAM version, 8Gb is not going to be enough even for basic stuff very soon, even right now it dramatically increases SSD wearing. I think it will get bad reputation and would be much harder to resell at decent price.