I think many people, especially SV devs whose job is finding solutions to problems, forget that there are no solutions to some problems. That only solution to these problems is to not pursue what causes the problem altogether.
Yes, it would be better if web applications that use canvas for their whole UI didn't exist. But they do, and I'm sure there will be more of them. I won't be able to persuade developers to stop developing apps this way. So I have to do what I can to help make them accessible, however imperfectly.
Right; to be clear, my issue is not with AccessKit or really any of the work you're doing here. I'm really happy that AccessKit exists, I'm glad that you're working on it.
AccessKit is trying to help fix a problem as best it can. My issue is with the people and frameworks that are causing the problem.