I think the Conservatives are done. Two years is a long time, but I think that people have made up their minds on both Johnson and the Conservatives. There is about 1/3 of the country who are just always going to vote Tory, some because they simply think anything the Tories do must be right because it is the Tories doing it, some because they are petrified of anyone else outside their 'tribe' being in control. There may be another 5% that can be put off but easily drift back when viewing something about the opposition.
The majority of the country will not now vote for Johnson or the Conservatives. The only issues are whether they will vote for anyone at all and how the FPTP/constituency boundaries pan out.
I think they are done. The impression I get is that most people have decided and nothing the Conservatives can do or say in the next two years is going to have any effect beyond a marginal one.
That said, I have a fairly average record predicting votes.