Best way to get this into legislative oversight is probably going to be via a ballot initiative. I don't have much confidence that the legislature can get past the lobbyists much less a probable veto. I can't imagine a D or R Governor turning loose of this slush fund under sole control of the executive.
The budget for the OTA is about 1/6 the TOTAL ODOT budget. It has been suspect for decades in Oklahoma. One has to wonder what they do with all that money given the poor repair of most of the toll roads I have been on. Same goes for the rest of the state that spends slightly more than average per capita for roads and clearly has far below average roadways.
https://okpolicy.org/resources/online-budget-guide/expenditures/how-oklahoma-spending-compares/
Oklahoma was once a good place to live. Not so much anymore. It is sorely mismanaged.