This is a tough one. So many people have contributed to make ClassicPress work. But it seems that, without a really clear mission, maintaining it is going to be a massive task.

I guess the question is: Aside from sidestepping Gutenberg, what is the purpose of ClassicPress?

If it’s vital to stay compatible with all current WordPress plugins and themes, then forking 6.0 makes sense. But can that effort be sustained for the foreseeable future?