On one hand, Shin Jinseo is an outlier player of this generation. On the other hand, the newest generation of new pros will have exclusively learned by using the AI to tell them what the best move is, so there's reason to believe that peak human level has yet to be reached.
Could someone sufficiently motivated invest in training Katago to be able to beat Shin Jinseo with 3 stones of handicap? Unfortunately - probably yes.
This in no way detracts from how absurd and remarkable it is that Shin Jinseo can beat KataGo (it gets a LOT of training and architecture refinements https://katagotraining.org/#eloGraphButtons) with 2 stones of handicap.
Depends on where you put the perfect play ceiling. I think each side has good points in their respective favor. There have been strong pushes by both humans and computers in improving their best play in the past few years.
A 2 stone handicap, however, does not scale linearly with strength. It becomes relatively more impactful at higher levels. For pro players, 2 stones are gigantic, and for beginner players, they make zero difference. Same for a point advantage (komi adjustment). So there might come a point where it is physically impossible for a computer to beat a top human under some handicap.
