Committee is pejorative and also a stupid word. There is no committee that meets and decides who should pitch which inning.
There is, however, a pretty competent bullpen which--and this will no doubt come as a surprise to you--has to pitch more than one inning to enable the Sox to win games. The 10th tonight was a big deal only because Cora foolishly sent his worst reliever out to close with a 3 run lead.
There are at least three guys I would trust right now to close--Ottavino (experienced closer), Whitlock (best reliever all season and definitely better than Barnes), and Richards, who has undergone a transformation since joining the bullpen. He's pitched 10.1 innings in 5 games, given up 1 run, and twice (last night and today) pitched--seamlessly-- in the 8th inning in a close game.
The point is--and I think I need to repeat myself here--the bullpen succeeds only if it keeps the Sox in the game before the 9th inning rolls around. Indeed, you can almost make a case that Perez got to pitch the 10th because six better pitchers, including starter Eovaldi, held the Guardians to 2 runs for 9 innings.