Sure. Buddha rejected the pranayama that bore him no result. Buddha realised the violent pranayama he formerly practised was a fruitless path. Buddha explained in his 1st sermon: Buddha did not teach of "sudden" full enlightenment. Full enlightenment is gradual. But the 1st stage of initial enlightenment, i.e., stream-entry, is certainly sudden. But sudden enlightenment is not full enlightenment. Buddha taught four stages of enlightenment. Kind regards