I think between Lee Bright and Richard Cash, Lindsey Graham has every right to be very nervous about his future.
I think you’re right - although I would add this to your statement: “...and his own absurd actions....”
An incumbent Senator of high profile, if he was doing even a so so job, would not be in trouble. LG is in trouble because he’s long since flown off the rails and become just another beltway tool.