As someone who has done exit interviews on both sides some quick notes: 1) I would dial back dramatic sweeping criticism. Now is not the time to relitigate every grievance, claim doom will befall company etc. 2) Treat it as any other feedback cycle. Here's what was working well, here some areas I might look at improving. Keep it light and friendly. 3) Do a slight "I" perspective. I'm moving for higher pay and to have…
This might sound unpopular but, when leaving a company I'm mentally telling everyone to f-off. Unless the the interview is with someone that could refer you, I wouldn't even waste any time or energy in that interview. It's not worth it. Miss it. Nobody will remember.
You won't be pushed that hard for an exit interview if it was pretty clearly not a good fit. Some of these transitions are a relief for all concerned (employee AND manager).
If a manager has someone with leadership / significant upside potential I do think a discussion is worth doing if possible.