To foster the adoption of FinOps do we need support from CFO OR CTO OR CIO ?
This will vastly change depending on how much IT, and by combination Cloud, is important in your business.
If you are making tableware, IT is probably less than 5% of your company spend, the CFO is NOT going to care. If, on the other side, you are a software company with a share price that might drop if the product is not launched on time, then you NEED and will probably get the support of a C-level person as long as you can connect your efforts with their targets.