The stem length affects handling, the handlebar reach does not. In terms of “reaching” the bar, it makes no difference if you go for a 90mm stem and 100mm reach bar or a 110mm stem and a 80mm reach bar. The sum of the reach numbers is still 190mm from the steerer tube, and the effective distance to the hood is the same.
However, a longer stem makes the bike handle more smoothly, and a shorter stem makes it more twitchy. For road bikes, anything over 130mm tends to feel awkward and sluggish, and anything below 80mm often feels very nervous. Most bikes are designed around a 90-120mm stem, so handling and geometry is optimised for a stem of that size. On road, going shorter is often much more noticeable than going longer in terms of stability and ride feel.
In your case, since your bike is a size 58, I’d recommend a 110mm stem and shorter reach handlebars. Your bike is likely designed around a 110-120mm stem from the beginning, so going down to a 90mm will make it ride very poorly as soon as the speed increases.