so it seems that iPad is the shitty one and iPad Air is the good one (and iPad Pro is expensive top of the line one ofc).

from 2019 is iPad Air 3 and iPad 7th gen, iPad has A10 from 2016 and 32GB, iPad Air 3 has A12 from 2018 and 64GB, and slightly larger display. Used iPad 7th could get for $120 but refurbished iPad Air 3 $153 "very good".