Percentage wise, he is. But Steph’s volume is nearly twice as much (he missed a bunch of games too).
Honestly, Steph’s percentage shouldn’t be compared to most players because his attempts are typically of higher difficulty. Not only is he often FAR beyond the line, but he draws so much more attention on his attempts than anyone else. Once he crosses half court, defenses are much more willing to contest him than anyone else.
That said, Buddy is right up there with the best considering volume. There are lots of players shooting a lot more than him (Boogie Cousins has a lot more attempts) but only 3 with better percentages. But considering how many he has taken, his .429 is phenomenal.