Having lived in one of those typical brexit/red wall areas for the past 20yrs, I'd say those who did vote for him/them did so for brexit reasons only and as far as they're concerned that's done now.
Nothing has changed for them.
There's no new money magically appeared for the levelling up.
Services are still being cut.
They don't really pay much attention to day to day politics, or what happens in parliament, they just liked what they heard and saw from Boris.
Remove him and I'd say most either won't vote, as they didnt before, or they'll go back to voting later.