The things is we think about it as zero drop altering our posture, but the fact is it doesn't alter our posture from what it should be (barefoot). "normal" shoes are the ones which alter our posture, and potentially cause damage.
Unfortunately decades of wearing them, realistically, can't be undone in a month or so, especially when, like me, you are required to wear steel toes 8 hours a day, 5 days a week.