If Usyk had beaten relevant HWs at CW I would factor this into his HW evaluation because historically CW is HW. He didn't do this though and relevant CWs who aren't relevant at HW are mainly relevant because of the existence of CW.
IMO Ali's Olympic medal has a bearing in regard to how highly he is rated as a fighter. He's rated very highly for having the one of the best resumes of all time at Heavyweight as well as having many memorable fights as a professional and because he won a gold medal in the Olympics.
I don't agree whether or not Ali didn't have a successful amateur career he'd still be the number 1 Heavyweight based on having by far the best resume as a professional at Heavyweight. That's what people look at when accessing his career in regards to how highly he is rated all time not because he won a gold medal in the amateurs that has little to no barring on it. For example Larry Holmes had a forgettable amateur career but yet most have him as a top 5 Heavyweight of all time his failed amateur career has no barring on his all time ranking.