While I agree most OPEC or Non-OPEC produce as much as they can all of the time, SA and a few others have enough spare capacity and can swing prices +/- 30% overnight. Total control, no. But can greatly influence while keeping themselves roughly revenue neutral.
Eh, I’ve worked a lot in Saudi. They do have spare production, but not a lot, and even less that is quick and economical.
There’s a literal giant underground front of encroaching salt water that they are managing well, but is a real problem.
If you want to look at the reason for price issues is the entire state of NM is effectively closed for new drilling.