the 2023 roster (assuming Chronicle gets in) looks absolutely untouchable. Every player other than Boaster is top 3 firepower in their role minimum and they have historically good support staff.
From the Americas region, I would say LOUD or Optic are close but they no longer exist and don't have any proven replacement. SEN seems to be the second best, or C9 if they pick up a few more players aside from Yay but I think Dephh is half the igl that FNS was and also that none of C9 match Fnatic outside Yay and Leaf.
In APAC, PRX and DRX are the only real competition currently.
In EMEA, I don't think there's a single team that is able to beat Fnatic.