Customer Success - Operations Department or Revenue Department?

Hey all! We are doing a re-org in 2023 and I wanted to get some advice from others here. Does Customer Success live in Operations? Revenue? Or Both?

Historically we have never had an Operations department, this all lived under Revenue so we are trying to figure out how to split it up.

Two things in reality:
1) SMB Customers
- We are an SMB driven business
- SMB customers make up: 60% of our customer base, 50% of our churn, 25% of our revenue

SMB customers have a 1 to many business model aka an unnamed CSM.

Which department should own SMB customers? We have dedicated roles for SMB CS (customer experience + automation)

2) Onboarding
- Onboarding Specialist + Trainer lives in Operations
- Right now 25% of our customers churn during onboarding
- How heavily should the Revenue team be involved for mid-market and enterprise customers?

Anything I am not thinking of or missing? To me it comes down to who owns Churn - both departments or one.