>seemed like no effort to make them look believably young either. how old are they supposed to be in present time? they looked at least 40 in the flashbacks, more like 50. flashbacks were what 50+ years ago?

i thought it was obvious that it was a choice that they didn't attempt to de-age them at all. they were just flashing back, but as their older current ages. like a memory you would have but while looking in the mirror. clearly Boseman is his younger self...cause he died in battle.
maybe I'm wrong...