It's pretty subjective, IMO. Judging how good a team is on paper vs what the manger got out of them is a multi-layered and complex undertaking, and even if a team underperforms or overperforms, we still never know how much the manager had to do with it.
IMO, Cora was gifted some good to excellent teams, early on and did well with them. The 2020 team was a joke. The 2021 team overperformed, and the 2022-2024 teams did about as expected. On the surface, I'd say Cora has done okay with what he had with 2021 being the one year we can maybe say he did very well. 2019 could be blamed on him for the same reasons.
To me, JH was more to blame starting w 2019's not replacing Kimbrell and Kelly with a budget that allowed for it, then it only got worse. Bloom is way more to blame than Cora, but that's not letting Cora off the hook, totally.
I once though Cora was the best manager we ever had, or at least tied or close to Tito. I no longer think that, but I like him and think he is a plus manager. Sometimes, however, a manger loses his team and needs to go. I thought that happened to Tito. I'm not sure about Cora and this team. It's an almost whole new team.