24GB almost surely is a waste for the typical mini user, regardless of cost we are looking at a spec-mismatch where the M2 Pro mini exists, and the higher RAM ceiling is supposed to be more useful along with the better SoC particularly in the 200GB/s memory bandwidth.
Now the guy narrows his choice down to M2 base mini with just the 3 RAM amounts as choices (discounting M2 Pro route), with 24GB out of the question 16GB sounds like a sweetspot for longevity. 8GB is actually quite likely to be enough for the projected 5 years of use but you never know if even websites or "consumer-class" apps will demand or expect a higher memory footprint in near future. Even (flagship) cellphones are expected to have 8GB nowadays.
The "33%" of price delta from the M2 base to the 16GB config as overcharged as it is, I myself think it is probably the one upgrade that makes the most sense. Just consider the 8GB base a heavy discount, where the 16GB BTO price being the regular price, if this makes you feel better.