Earlier quoted context omitted.
The problem is ambient go knowledge. A top 100 player would easily beat time traveling Lee Changho in his first few matchups. Of course give peak Lee Changho a fortnight to prep with Katago and … well that would be something!
It's not obvious to me, but I lean towards saying this is false. The 2026 player would play a better AI inspired opening, but I'm not sure that would be enough to overcome the skill difference. (This is especially true if they don't get briefed "this is time-traveling Lee Changho, he doesn't know contemporary joseki, play a trap variation").
The reason I think the top 100 pro would win is that when I watch pros review they are very quick to catch when someone is playing a non-current or up to date style. I’ve also seen a few middle game situations where the classic famous go move is now “obviously” not good after we’ve seen how AI handles it.
This all adds up to many ways good sound moves to Lee Changho have now obvious responses. Do I believe he would adapt inhumanly fast? Absolutely! Legendary fighting spirit