People on this site often use the verb “are” to describe Sentinels, the team, as well, so honestly most vlr.gg enjoyers would read “Sentinels are overrated” and think of the team Sentinels because it is a 5 man team, making the subject verb agreement somewhat grammatically correct if you look at it each individual player as a Sentinel, because technically they are. This makes multiple players on the same Sentinels roster a plural subject, which would require a plural verb to go with it.