It's down to outgoings versus incoming and what sector you work.
If you are public sector you are pretty OK. But public sector work doesn't generate income. It supports society.
If you are private sector of any kind you are much more exposed (but with some exceptions). This is where the economy is driven.
In terms of working class versus middle class its definitely true that middle class tend to be in jobs more able to work from home purely because they are white collar jobs. But you also have a considerable number of self employed and contractors in the middle class who haven't had quite the same levels of income support in comparison to their normal outgoings (larger homes = larger bills and bigger mortgages), thus they might get in deep shit very quickly although they might not currently as close to the breadline as those on lower incomes.
If you are middle class you tend to have better terms in your job (things like sick pay and pension) and less likely to be on zero hours contacts.
Tbh I think it's a bit like comparing apples and pears.
There are lots of working class who are facing being first to lose jobs after furlough ends and if they are still working tend to be more exposed to Covid-19. But there are plenty of middle class who will stand to lose everything - their business, their home, their community / friends (as they are forced to move to cheaper areas). And others who will be just fine and might even do quite well out of it.
Overall what will happen is a shrinking of the middle class and even greater economic inequality, with those at the very bottom worst affected. So many of both the wc and mc are going to be utterly stuffed including some who have had up to now very comfortable lives indeed.
One of the people I know who is most in trouble has a house worth about a million and a half but the business is now worthless and they can't pay the mortgage and since he has a chronic degenerative illness his long term earning potential and security for the family which he'd built up is going to be completely wiped out. He's already in his 50s but his youngest is still just 4. I can't see a happy ending for them.