You might want to look at the U.S.A roster.
USA has 5 players from its World Juniors roster. 3 more 20 year olds, 3 more 22 year olds, 5 more 23 year olds.
Putting the best Juniors you have appears to be a pretty good idea, but just bringing along the whole team is likely not. Too early to tell but USA's "go young" supplemented by old guys appears to have been a better strategy than Canada's "go old" supplemented by young guys, we'll see how the knockout round shakes out all the same.
There's a pretty big 4-year difference in development between 23 year olds and 19 year olds though. The 19 year olds that USA (and Canada) brought are all very high-end with high NHL potential. Dunno if there's the "issue" that less Canadian guys play NCAA hockey so more 22-23 year olds are already under NHL type contracts and either in the AHL or NHL. Dunno what the protocol was for releasing "tweeners" (if NHL teams kept them off the list because they may need to call them up due to injuries/COVID/trade deadline stuff)