Goku says about 5 times, that under no circumstances do they stand a chance against Buuhan
He BEGs and PLEADS to vegeta to fuse. Visibly terrified of Buuhan (he even gets smoked by Buutenks who is weaker than Buuhan and hangs with Kid Buu better than he did Buute ks)
Goku fights and maintains that if his living body didnt havr such a stamina drain with SS3, he could likely generate such a notion vs Buuhan
This is legit willful ignorance on your part
It makes no sense to ignore the text where Goku openly admits his own arrogance, explicitly stating they should have used the Potara earrings. Throughout the entire encounter, Goku was completely ineffective against Kid Buu, who was visibly toying with him. To argue otherwise-