"Before" and "after" are generic terms. A car might stop before the crosswalk (space). You might eat dinner after work (time). But "ex ante" and "ex post" specify a relationship to an (random) event or to specific information. For example, a data scientist might compute a quantity "ex ante". This means that the quantity was estimated using only forecast data. No historical data was used. It would not make sense, however, to say that a car stops ex ante the crosswalk.

I could have easily said "afterwards" and "beforehand", but I like "ex post" and "ex ante" when referring to before/after having access to specific information.

Got it. I will try to leverage the synergies between Latin and English ex post.

it conveys that you know what ex post and ex ante mean

Or, quite often, conveys that you don’t know what they mean.