The post you replied to was a hypothetical if/when all three of the Big Three make the team.
Regarding Campbell so far... yup, ST stats don't mean a lot to some people, but the games are what we watch, and the most recent qualitative data.
As for where Duran plays when Anthony arrives, this isn't quite a Jackie Bradley/Mookie Betts comparison. Obviously, Mookie was good enough to be the centerfielder one year, then moved to right for JBJ. In their first season together, both were All-Stars and the Sox went from worst to first. It wasn't a bad shift; Betts won five more Gold Gloves than Bradley.
Duran played a little right when he came up in 2022. According to bb-ref, his Defensive Runs Saved Above Average that year was +52 in RF, -26 in CF. Last season in CF Duran was +25, Rafaela +23. Abreu was +22 in RF.