In 1997, Deep Blue beat Gary Kasparov, the world chess champion. Today, chess grandmasters stand no chance against Stockfish, a chess engine that can run on a cheap phone. Yet chess remains super popular and competitive today, and while there are occasional scandals, cheating seems to be mostly prevented.

I don’t see why competitive debate or programming would be different. (But I understand why a fair global leaderboard for AOC is no longer feasible).

Online chess competitions actually spend quite a lot on preventing cheating, and even then it's a common talking point.