As far as series parallels go, the World Series against the Astros feels more like the 2018 Tampa series.
Both the Astros and 2018 Lightning Best team in the NHL by consensus. Not many weaknesses. Supposedly better in almost every category over the Caps (Nats). Almost every major pundit along with Vegas (Sportsbook Vegas) favoring Tampa (Astros).
This is the David vs Goliath scenario all over again, although the Nats have already taken one down in the Dodgers (Caps taking down the Penguins)
So perhaps a little out of order:
Capitals-Blue Jackets ---> Nationals-Brewers (gritty comeback early round victory, moment where things did not look good)
Capitals-Penguins ---> Nationals-Dodgers (first demon slayed, the "BIG" one, the proverbial hump, finally got past)
Capitals-Lightning ---> Nationals-Astros (David vs Goliath, against best team in the league, heavy underdogs)
Capitals-Golden Knights ---> Nationals-Cardinals (both series were finished in 4 or 5 games?
)