In the US, you have a few prominent ways of defining class. The most popular is very amorphous and based on cultural signifiers: Someone might be considered to be in an upper class if they have a nice car, even if they might have that car on a loan and are living out of it.

Or maybe they are upper class because they have an education, even if that education has not produced employment and put them in more debt than before they had the education. Maybe they are upper class if they are eating out, even if they themselves are a restaurant worker.

Another way is a sort of strict orthodox Marxist definition which defines workers as those without capital who are waged workers.

While this latter definition is more correct, capitalism has evolved to show us it has numerous ways of exploitation without waged work. Women have always been subject to this through unpaid domestic labor.

But autonomist marxists would include many other categories traditionally excluded from orthodox marxist definitions. Students, youth, the imprisoned, the unemployed, those on social benefits, the enslaved. Because capitalism & colonialism finds ways to exploit all these peoples.

What all these people have in common is that they don't have capital.
In recent years, this way of looking at class has been reaffirmed by the most prolific rebellions being led by those traditionally excluded from orthodox marxist definitions.

It has been unpaid domestic workers, people in prison, the unemployed, etc. who have most ruthlessly attacked and expropriated capital. Some of these categories orthodox marxist might have once (rather derogatively) referred to as the lumpenproletariat.

But a different understanding of class might change what we think of as class consciousness. After all, if we are to engage in class struggle because we are exploited and oppressed wouldn't it make sense that that class struggle originates with the most exploited and oppressed?

Those who have been most marginalized by this system are engaging in class consciousness by their very act of destroying it. To loot and annihilate the commodity form is an acknowledgement of the proper owners of stolen and dead labor. Even without flags declaring class.

The struggle of the working class is a struggle about the autonomy of the most marginalized within the working class, because what defines us as a class is born out of that exploitation/oppression that they are the most acutely impacted by.

This understanding of class is what we need to embrace and expand upon now. Here is a video that defines class similarly: