Let's see...
"Machado is a top defender at 3b"... he was at one time.
2015:
7th of 20 qualifiers in UZR/150, 3rd in DRS (Defensive Runs Saved). That's very good.
2016:
2nd of 18 in UZR/150 and 4th in DRS. Even better than 2015.
2017:
9th of 18 in UZR/150 (dropped from 9.9 to 2.2... losing range!) and 7th of 18 in DRS (dropped from 13 to a mere 6). He fell from very good/excellent to slightly above average.
"above average at short"...
in 2018 Machado's defense ranked 22nd out of 22 qualifying shortstops. I suppose you could say that there's nowhere to go but up!
Obviously Manny should be at 3b going forward. And while it's possible 2017 was an aberration, he's two years older, so a return to very good/excellent defense would seem optimistic. But as of right now, "top defender" he is not.
"Harper is above average in right field"... I posted this already, but happy to do an encore showing Harper is pretty much the worst defensive OF in MLB among qualifiers.
#57 of 57 qualifiers in UZR/150... meaning he has no range. And
56th of 57 when measured on DRS with an abysmal -26 (saved from the bottom only by Charlie Blackmon's -28, which was half compiled in Coors Field, one of the most spacious CFs in MLB).
Don't know what else to tell you, other than if you're relying on the eye test, might be time to get a new pair of glasses.