I understand that, but the argument given by the Reformers is that the early Church went off the rails and therefore lost its legitimacy not withstanding Apostolic Succession. So even if the Church retained one sign it was founded by Christ her adoption (in their eyes) of extra Biblical doctrines overrode that.
Which is why the solution is to go to leadership that has no connection to the Apostles?
See, this is the problem. Even if the reformers are correct, that’s not enough to get you to the answer “I must join with you”.
If they say that Apostolic succession is unnecessary, then they have to explain where their authority comes form.