The big problem the Tories have is while there are a lot of people in more traditional Tory areas and with traditional Tory mindsets (no idea whether you are in this camp or not, more a broad observation) who aren't keen on him and want him out, but then you have the "new" Tories in the Red Wall who love him and almost certainly wouldn't see any value in swapping him out for (e.g.) Michael Gove.
Finding someone who can unite these two camps will prove to be a struggle. Sunak is probably the only one I can think of who might be able to do it.
I’m not sure whether you are referring to red wall voters or red wall MP’s. However, I think a considerable number of both are probably, and quite rightly, pissed off with him.
Once Johnson goes( and I think he will, but perhaps not soon enough for me)there will be an opportunity for his successor, whoever that might be, to do a ‘Hercules on the Augean Stables’ and completely change the culture of Government.
At present, it is an embarrassment for the country and decent MP’s of all political persuasions to have such an appalling man as Prime Minister.