Recommended purchase: Smart 451 vs. 453

Hello, I need your support when buying a smart. Smart, because only the size is possible because of the parking situation in the Cologne area. I drive computerically almost 7-10TKM a year, of which 70% city, 20% country road and 10% highway. I want to drive the smart car 1.5 – 3 years, need high flexibility, because the running time depends on when my girlfriend moves to Cologne. Actually, automatic would be extremely important to me, but we also come here to the discussion or to your support : idea 1) New model, used A young use with 10TKM for 8-9T€ (then with leather). Unfortunately this does not correspond to my wish, I would like automatic, but then costs 11T€+ (over budget) idea 2) Old model Smart 451, from Bj 2012 it should be very stable. Here at least 71 PS and with under 50TKM I find decent starting from 5T€. Conclusion: New car too expensive and no flexibility, but rather an old or young used smart? – Feels the purchase costs for the young smart are once high, but with a gross calculation of the same value for the old price?